I think what you are essentially asking about is POI (Points of Interest) integration, something that I understand is on a to-do list. However, there is, I believe, a significant difference in adding POIs from an underlying database (OpenStreetMap) and from users.

Specifically, in relation to wild or stealth camping I can see several issues.

How do I know it's a genuine location and not someone having a joke? Or worse?

How do I know it still exists? The utility of a "stealth" site is directly related to such extra data and possibly "reviews" which makes it more complicated.

There is an outside chance that someone who had a bad experience at such a location could vent at CT - legally. Any legal threat, no matter how insignificant, is a drain on time and money.

That then leads to the legality issue. Wild/Stealth camping is illegal in many places. A popular navigation app assisting people to break the law? Tricky.

And potentially other things to consider. I recently read of a case where a family home was listed as a hotel on B00king. Cue a lot of irate people on an innocent family's doorstep.  

There's also the matter of how long a stealth campsite could survive if its position was made public.

Personally, I treat wild camp suggestions from others with a degree of scepticism until I am in the area and get a feel for them. I would never depend on them. A part of the process is finding a place that is good for me att hat particular time and place, no?

However, if you have places that you want to use it should be a simple matter of putting the coordinates into CT and plotting a route. A secondary app, such as Osmand may be helpful for recording multiple sites in one place. 

A camper like app for search spot like park4night, people can upload coordinate,photos and writer something about.Should be interesting if It was integrated in C.T app for long bike travel.