Why Are Old Guys So Creepy?

Although it is possible your friend is unintentionally giving some signals, "creepy" people are that way throughout the world and generally throughout their lifetimes.  The tendency seems to be as people grow older, they care less and less what others think of them, and so may be bolder in their actions.  People who have social behaviors that are outgoing and welcoming seem to be more at risk of encountering the advances of others prone to look for welcoming, friendly behaviors.

I don't believe that others' behaviors generally encourage that behavior, and I don't believe your friend is responsible for someone else's bad behavior, but maybe what you can do to help your friend would be to advise her reaction.  It would be good for your friend to practice asserting her boundaries when it DOES occur.  You know your friend better than anyone who is answering here, naturally, but observe your friend, and encourage her (practice with her if you  need to) how she can comfortably but firmly reject such ridiculous and uncalled for behaviors.

You sound like a great friend to be concerned! Good luck! :)