(1) failure to disclose one's status or, (2) lying about one's serostatus; (3) agreeing to use condoms, but disregard this agreement; (4) agreeing to pull out, but disregard this agreement.
I wouldn't consider your #1 stealthing. If the partner wants to know the status of the other and he lies then we're on to your #2. I wouldn't consider #2 stealthing because the bottom is making a conscious choice to believe what their partner is saying. And, for what it's worth, it's very possible that the HIV test done last week showed neg, but if tested today even without additional sexual contact he could be poz.
I don't understand #3. If you mean that they start out using condoms but end up not, it would only be stealthing if the bottom wasn't aware that the top ditched the condom. I believe this is real, but perhaps not of the frequency we hear.
I also believe #4 is real but I also believe that in most cases the bottom knows what's going on and in the heat of the moment doesn't object. If the bottom really wanted the top off him that can easily be done using pain if necessary, unless the bottom is restrained, and that's an entirely different topic.
There's also the "compromised" condom, where the bottom believes the condom is functioning but the top damaged it intentionally. Again, I think this can be real but probably less frequent than ditching the condom midway through the fuck.
Anyway...my 2c