Yup. Knew one of the guys that worked for the NFL doing just that. He was retired local and federal LE. He never mentioned a concern over off duty cops with guns at games. He left the job a couple years ago though.I think I can understand the NFL decision from a different viewpoint. The NFL is a smoothly run big business, and the games are a big deal. There's a lot of security planning, in fact the NFL has its own security division (which I presume works with the local stadium venues to ensure that there is a comprehensive security & emergency plan in place for games - coordinated with the appropriate local LE agencies).
A very real concern. But that is something officers deal with all the time. It is always a possibility and even more dicey when it involves an armed citizen. There are some procedures that help reduce blue on blue. Even then, the risk is to the off duty guy intervening. He knows he is taking a risk and knows how to protect himself or communicate his intentions and ID. He poses virtually no risk to uniformed responders or the public. Off the top of my head I don't know what sort of grand security plan a single off duty guy could muck up. If he sees a guy blasting away and can take a shot he does. How does putting an active shooter on the deck ruin a preplanned security response? Drunken brawl? Probably stay out of that one without back up or proper uniform unless it get's deadly.So if there is an incident (large or small) at a game that has to be handled in accordance with the security & emergency plan, do you really want an unbriefed, armed & possibly intoxicated off-duty LEO - whose intentions are unknown - wandering into the middle of the incident to do something? And by intentions unknown, I don't mean he/she's contemplating criminal action, I just mean planning to take some LEO action that's not unreasonable on it's own, but is unbriefed and throws a monkey wrench into the pre-established security and emergency plan. That has a real chance of not turning out well.
In the end it all comes back to alcohol. Clearly anyone with a gun should not be drinking. I just don't know why there is the assumption that every off duty cop that walks through the gates is going to get drunk. Can't you enjoy a game without getting blotto? I am quite sure their agency has a policy about drinking with a weapon. They know they expose themselves to huge liability and possible criminal penalty if they use a gun while intoxicated. But there is an assumption that they will drink. Where is the evidence this is a problem? I am very sure some guys drink, and to excess, when armed. They shouldn't. But I don't see evidence they are posing a uniform threat at NFL games. I suggest it is far more likely you will have armed citizens at NFL games that are not going to be as well trained or responsible as off duty cops. Even then, not exactly epidemic.