Actually, when I was in my 20s my friends didn't know I was cruising the park at night looking for sex. The only ones at the clubs who knew were the ones who would be there themselves. When I saw them I knew I would see them later on at the park and they knew they could have my ass at the park if they or I wouldn't hook up with someone else first. Like I didn't tell my friends they wouldn't admit to their friends where they knew me from. Sure, I had guys come up to me at the clubs who I recognized as friends of those who fucked me in the park so they must have been told I was "easy" (without telling them how they knew I guess) but at that time I was picky at the club (looking for a sexy potential bf) and didn't care who fucked me in the park (just looking for sex) ;-) Never felt it hurt me in any way though as my reputation as a slutty bottom was only with those who were looking for quick anon sex themselves. And at the time I didn't mind that.
Now I couldn't care less. I don't have a partner, just a few fuckbuddies and anon hook-ups and for the moment that is fine by me.