The Reality Paradigm
A sufficiently advanced technology is indistinguishable from magic... and vice versa
As a general rule of thumb, start with current state-of-the-art technology. Add second edition M:tA rules, and simmer gently. In short, thanks to the the efforts of Hollywood (and Sony) most of the world tends to be tolerant of effects which resemble existing devices, even cutting edge technology. (Yes, Virginia, there really are lasers, stun-guns, kirlian fields, and thermal imaging devices, and if you can show me that such a device really exists and present it in a reasonable manner, consider it to be coincidental.)
Likewise, if your character has been built around a performance concept (action film star, TV evangelist, stage magician, circus performer, or mentalist) or paranormal concept (research psychiatrist, Zen master, Taoist magician, shaman, New Age mystic, etc.) the bounds of disbelief can be pushed back a little if you're working within the concept of your character. The constant low-level media exposure to the fantastic exploits of martial arts masters and New Age mystics has been somewhat less successful in securing a place in the everyday life for the fantastic and unusual, but the possibility that there may be more going on than meets the eye when the crystals and yoga mats come out has at least gained a foothold in the subconscious of most people. Faith-healing, while not an everyday occurrence, isn't entirely unheard of; the miracles attributed to them usually tend to be limited to tent revivals, just before they pass around the offering plate.
If you can read about it the newspaper, it's probably coincidental. If that newspaper is the Wall Street Journal, it's certain coincidental in New York. If you're relying on the National Enquirer or similar tabloid as your source of information, an outlandish feat may still be coincidental, providing you're only doing it in some of the more inaccessible and remote places on earth; usually, the places to which the tabloids attribute outlandish phenomenon tend to be in the remote Andes, in Africa, or in the remote parts of Asia.
With the right character concept, the Blatancy talent can help to ease some of reality’s restrictions. Rocket scientists, electrical engineers, special effects engineers from Industrial Light and Magic (or most movie studios), doctors, and physicists can all get away with pushing the envelope of wonder and disbelief; it's what they get paid to do, after all. Stage magicians can also get away with a bit more than, say, your average librarian, because people expect a magic act to include things like levitation, making people and objects vanish and reappear, and causing items to be damaged and restored whole again... to a point. The key to making blatancy work is to show people what they expect to see, whether or not they actually understand it, or to offer them a reasonable explanation.
Two words can be used to categorize magic: coincidental, and vulgar. Coincidental magic is just that: the mage makes use of everyday occurrences to maintain a degree of deniability. Keep in mind that coincidental means subtle and plausible. Chances are, if you're playing down the visibility of magick, people will readily attribute it to something else. Ideally, it can't be traced back to the mage by anyone other than a mage, and if it can be, there should be a reasonable, rational, non-magickal explanation. In short, with coincidental magic, chances are good that only another mage would be able to tell that things were coaxed along a bit.
Cautious mages tend to avoid close association with those mages who flaunt Reality at every turn. Paradox is, of course, the first thing that comes to mind when someone starts thinking about tossing fireballs in the crowded parking lot or making functional wings out of beeswax and feathers. While it is a consideration, particularly in those instances where something goes awry, other not-so-obvious complications may arise as well.
Overt magick or "vulgar" magick tends to draw lots of attention. Sometimes, in a life or death situation, a mage has to grit his or her teeth and do what needs to be done, in spite of the cost. Where ever and whenever possible, however, a wise mage takes precautions to avoid being placed into that sort of situation. There is good reason that they say there are bold mages, and there are old mages, but I've yet to meet an old bold mage... at least, on this side of the Gauntlet.
Admittedly, Mage is about fantasy, but keep it real and keep it reasonable. While it might be gratifying to show off a bit by leveling a city block or two, it's not the sort of thing that gets ignored or goes unanswered. Rest assured that if you have coincidental thermonuclear hand grenades, chances are good that the bad guys do, too. And even if they don't, you can bet that once you initiate a thermonuclear hand grenade, some person wearing a company X uniform with a name badge that reads "Murphy" will have the destabilizing particle projector to cause premature detonation, or the dampening field that keeps the components from going critical until he or she has you exactly where he or she wants you.
Keep in mind that the Technocracy opposes "superstitious and irresponsible" use of "magick", both overtly and covertly: numerous vacancies can always be found in for an extended stay in "reeducation centers", where hundreds of misguided souls have been made to see the error of their ignorant, superstitious ways. Too, sleeper society can easily panic in the face of the unknowable, the uncontrollable, or anything that is different from "normal"; though it's seldom called such any more, it takes very little to incite a witch-hunt. Madness and corruption await those who stray too far beyond the bounds of normality. And finally, members of Traditions or Crafts (or any other secret group in the World of Darkness) don't want to get swept away by a mob or a government agency because they happened to be in the wrong place at the wrong time. Even the more tolerant champions of traditional magick don't put up with a loose cannon in their back yard for long; irresponsible activities which draw attention and potentially jeopardize everyone around you will most assuredly not put you in the good graces of your neighbors, no matter who they might be.