Best noise making ideas!

Disagree on the bad sportsmanship, when you’re in the middle of a roaring crowd blowing the whistle is not nearly as distinguishable as you’re thinking, it blends in and is just very efficient. Now if you’re prancing around security guards on the isle and using it when the crowd is not loud then it would be obvious (see video in this thread of troll in this using it during a punt at a Seattle game). Myself and multiple friends have been using whistles consistently all season now, it’s not as blatant as some hyped it up to be because when we’re on defense the dome is already so loud. We’re just trying to make it the loudest
If its common where you sit, then I stand corrected because I've not heard whistles. I know whistles are specifically listed as noise-making devices that are not allowed NFL stadiums but I'm sure security has higher priorities than plastic whistles. As with everything, a little common sense and it's probably fine. Same for plastic bottles with caps.

If some drunk blows one at the wrong time and costs the Saints a penalty, it may get more attention.