There's no 'should'... players are there to enjoy themselves (in a session, I presume you mean) and the session will sound different depending on who's there.

I suppose if a dominant instrument, like piano accordion or pipes were making it hard for others to be heard the player 'should' have the sensitivity to put the instrument down for a bit to give the others a chance.

But as with everything else in life, sensitivity to other people makes things go more smoothly.