If one's selection marking dead stones gets refused one will have to play a new stone in order to verify that the stones selected are dead indeed.
Indeed, you can be forced to play new stones:
opp: pass
you: pass
opp: marks dead stones
you: accept, mark dead stones
opp: reject
you: must play a new stone
opp: pass ...
You can break this loop either by refusing your opponent's selection (so he will be forced to play a new stone), or, when your opponent does not mark any dead stones (so you can't refuse them), by not marking any dead stones either (the match will be evaluated then).
OP