I have done breast bondage with ribbons, so that really no one will second guess that I have it on. No bra with tight a shirt that isn't loose fitting, unless someone is really staring they cannot really know.

I have also worn a crotch rope set high enough with a top that barely covers and have bent over to reveal it in a public area. No one can get offended unless you are being overly flamboyant about it.

I have worn a dog collar in public, but with a top that could make it visible.
I was constantly aware of it, although I doubt others were.