Is not the runway number printed on the end of the runway ? ( I would guess that they would start the t/o run from the very end of it)
Would it be an idea at certain airports to 'check' your heading with the runway you are supposed to be using or that both pilots confirm they are on the correct one?
Would it also not be prudent at (certain) airports (where confusion could arise) to have a clear illuminated sign with the runway number on it too?