I've had two acoustic basses, neither of them could be heard in a session unless I used a battery amp snuck underneath my chair. The acoustic bass looks a lot less threatening than it's electric counterpart. I can't recall any objections or snide remarks but I don't take it now because my guitar and bouzouki technique have improved (I still use it in a ceilidh band). I do agree that used sensitively, it can enhance a set of tunes, but the trick is to know when not to play it, something some other session players ought to learn too! I prefer to use index and second finger rather than a pick. It helps with speed and produces a warmer more integrated sound - the click of plectrum on an acoustic with no amp was more dominant than the note.

I take the strings off now and again and soak (and shake) them in a jar of meths. They are strong enough to survive this several times (unlike a guitar). In fact, I haven't bought a new set of strings for about ten years! Unfortunately, my guitar and bouzouki have a nasty string habit if I want to keep a decent tone.