How do you know that you didn't cross the line? Perhaps those people just didn't want to pick a fight with you there and then?
The first you learn of it is when the cops come up and interview you.
You indicate ignorance and also that you think the woman was a shit for dobbing you in.
You indicate ignorance and also deep remorse - you're genuinely hurt that you harassed this woman and potentially several others.
You indicate ignorance and feign deep remorse - you actually think the woman was a shit. You bring up sex with strangers again and the police see that you have form.
There's a difference in what's going to happen in these cases. The fact that the police think it's worth investigating a report of a crime doesn't mean they'll react in the same manner to different circumstances.