backup beepers - protocol and rules

Are there rules or social protocols prohibiting backup beepers on rigs? The backup camera on our new-to-us RV reminds me of the cheap little black and white TVs we had years ago - the ones we thought were just fine until we could afford a better TV. I could probably see an elephant in it, if the elephant were dancing around and waving at me; but it's often pretty hard to tell what the picture's showing.

One option is, of course, to upgrade to a better TV or maybe a better camera. But I'm also thinking about a backup beeper.

These are, granted, irritating things if you're not behind the RV, about to get run over; but they're sure handy if you are in that situation.

But maybe it's considered gauche beyond words; or maybe some federal, state, or other parks won't allow them.

I'd appreciate thoughts and advice.