I am VERY uncomfortable with unwanted advances and tend to come across as a cold or aloof bitch...if the person persists and I am not interested in that sort of attention then either of my significant others is more than willing to explain to the offender the benefits of stopping the behavior. If it's a friend of my SOs then they would know from the outset that it's not appreciated unless I indicate I am interested to my SOs FIRST. One of the benefits of being poly I suppose but really all couples should do this for their lovers...as well as believing them when they admit to feeling uncomfortable. A friend, even an old one you've know forever, should respect yours and your lover's boundaries.
Coworkers have laws to govern their behavior! Personally, I didn't get real close to mine, when I worked....I was openly pagan and just a bit weird. LOL Being an adult survivor of alcohol abuse I tended to keep people at arms length. I was also usually right in the middle of highly inappropriate conversation so it wasn't really an issue. If someone got rude or pushy I simply froze them ouot.
With family, however that is a sticky subject as you are just as likely to be blamed as believed. That one requires major trust on your partner's side but I always believed in giving my lover's the benefit of every doubt. Still I don't tolerate it...but if it's a 'beloved aged elder' I might let it pass...or ask my partner to. It really depends on the circumstance. For instance my Great Grandmother would make playful passes at my husband...no big deal but my Aunt accused him of raping her....BIG deal. Yes I know, my family is fucked up....