I do expect some interference.

Although we have not done testing with camera flashes, we tested sensor response times a few months back while trying to debug some balky program (when sensor based termination of an unlimited move did not work consistently -- this is a known problem, with numerous solutions).  We found that most of the standard Lego sensors have millisecond response times (I even remember seeing a website where such results were posted).  These response times are consistent with duration of modern camera flashes/strobes (same order of magnitude).

Thus if you have calibrated the sensors to distinguish light from dark (or white from black), and then program using the same sensors (e.g. white is anything above a threshold level), you can have situations where grey or black can appear to be white if the ambient light level changes (such as with a bright flash in close proximity).  I am guessing that the problem will be minimal if the camera flash is held 10 or more feet from the table, or if a diffuser is used.  There are also a number of light/color sensor settings that can affect my response to your question.

Scott Evans, the FLL game designer recommends that the light sensors be cloaked so that ambient light is blocked as much as possible -- he would recommend a light sensor mechanical design that would let the sensor work the same way in a coalmine or bright daylight.

Our kids have never found the time to construct good quality shielding . . .  maybe one of these years, they reach far enough to make it worthwhile to research/invest this technique.  Right now our teams' design philosophy is based on design and programming simplicity -- I counsel the kids to avoid program bloat, even if this stops them from showing off all their skills to the robot design judges.

Best,

Nari Narayanan 
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Anant S Narayanan
McLean Robotics Institute
McLean VA 22102
202-421-3826 (cell)
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