So what? You think that two 16 year-olds don't make noise during sex or produce other indications of sexual activity? I don’t see what the age of the parties has to with it other than in some states that 55 year-old might be looking at statutory rape charges for having sex with a 16 year-old.
Where are you getting that they are both 16? For that matter, where are you getting that they are both minors? Or that either one of them is? Just because they live with their parents? My kids lived at home until they were out of college, and one for several years after.
I don't see where the OP has indicated ages of any kind.
He doesn't say he doesn't have funds; he says he doesn't want to spend them.
The OP is a troll.
The OP is unquestionably an idiot, I'll give you that. Troll is also a distinct possibility.
Wow.... Hopefully the floater won't ruin the moment... :P
Seriously, get creative. Or better yet, wait till marriage and do the right thing. I would be offended if I walked into a restroom with my children and two people were doing their business in there even closed door or not. I would probably ignore it... However at park bathrooms since they are dingy typically, I usually pay attention and recognize if there are other people in there. I probably would not call the cops if it was a concealed thing, but it may be "public ludeness" and please know, I typically don't call police for stuff.
If you are paying $40 each time, why not just get married and go into an efficiency together for probably not much more.