[Patrik]

Mirrors have opposite incident angle reflection, so unless the mirror is perpindicular it fails and only then it will be unlikey that the the mirror will be perp. for more than a few fractions of a second and hence the system will not mistake it for the retroreflective tape that is on the goals. I am sure the program will not be ruled by a one or two false readings.

I don't think that the red light will affect the infrared sensor. I admit I haven't tested against this but I am willing to bet that the output is polarized in such a way that it should prevent most false outputs (except for other sensors). I don't think the "Dean and The Crew" would have let sensors that could be affected by the safety lights (these are red remember).

I could believe heavy sunlight would affect it, it has a lot of light in every wavelength. I know some of the lazer tag sets (IR guns and sensors) are affected by sun, but I still have a hard time believing either of the mentioned scenarios would affect the sensors to any great amount.