'Notamed closed' question

OK, Here is a question for some of you FAR legal experts out there. I can't
seem to find anything definitive on it. If an uncontrolled airport is open to
those based there but notamed 'closed to transients' do the runways have to be
"X"ed?
If not what about a passer-by who didn't intend it to be part of his flight
plan but decides to land, say for a drink of water etc., or just to rest up?
Does he have to radio an FSS to check if everything looks good on a fly by?
What if he has no radio? Has a violation been committed?

Jim