it doesn't matter wether malicious or not.
Deciding wether flight crew are fit for duty has **** all to do with the security people. Perhaps if the just did their own job well instead of trying to play billy-big-balls and do everyone elses then it would be a slightly better place to work.
If rent-a-cops want to to this then fine, send them on a course, give them a breathaliser and let them make these accusations to peoples faces. Otherwise they are just little pathetic men pretending to be big men because they can hide behind their own anonimity.
FWIW I'm always polite to the security people and often have a chat, especially if its at oh-my-god-o'clock in the morning, when we all need a bit of lively chat, and 95% of them are good people but even with this positive attitude I still come across the odd one who just has a chip on his shoulder and wants to be nasty regarldess of how nice anyone else is.