I've heard it said and believe 100% that deer pattern hunters way better then we pattern deer!
I had one chap buy a 2nd camera, infrared sensor. Set it up to watch the area of the first flash camera...he caught a BUNCH of deer circling around away from the flash unit...
Wensels say if you put it up high, it doesn't bother them...I'd guess IF a bunch of people have been toddling around with flashlights, light might be a bigger factor.
This situation was on a heavily posted block of 20 acres, and nobody showed up on either camera "toddling around"... they just avoided the flash camera!