Since you mention Grindr, I remember in my company there were guys who would sign up as gay, just to see who in the company (and I guess in their social circle)

Since you mention Grindr, I remember in my company there were guys who would sign up as gay, just to see who in the company (and I guess in their social circle) was secretly gay, and tell it to other people. The irony is that they would find other guys doing the same.