Now that you guys were talking about Grindr and gyms, I had an experience about 2 years ago, that was pretty embarrassing.
I used to have my face clearly shown in my profile. A guy started talking to me in Grindr, saying that he went to the same gym as me, that he had seen me there many times, and asked if I wanted to suck his cock in the restrooms. His profile was totally empty, no picture, was he was up to,... only his age: 30. I don't answer to people who don't have any pics, unless they send some by private message. This guy just talked, no picture, so I ignored him.
He used to send me messages over and over again, saying the same things, but no pics at all. I asked him once who he was, and he told me to go to the restrooms so I could check it out and suck his balls by the way. I got so angry, that I finally blocked him.
It was very embarrassing for me to go back to my gym those days, and for many months as well. I felt like a stalker was watching me all the time. It's been two years since then, and I still don't know who that guy is. I don't care about this right now.
In conclusion, be careful when you upload your face to Grindr. There are some weird people out there.