This stadium is very safe and they have the protocol to prove it. Check out the security protocol on the website if you are in doubt, they will enforce this stuff.

Gillette Stadium is one of the safest public venues I've ever been to. There's a large security staff, video cameras everywhere, and slew of local police officers during game days. I've been to many games, and never had a safety issue. It's safe enough to bring small children without worrying about their safety.    

The stadium is very safe and they have great on site stadium security as well as Boston's finest. They are there to protect its citizens and have done a good job in the past.