Too much copying from other developers:

Nothing prohibits cloning an app unless you have a copyright/trademark.

And cloning a paid app to make it free is common

Copyright is automatic.

I'm not a lawyer, but I think automatic copyright is meaningless unless steps are taken to establish / defend it.

blog.traklight.com/is-copyright-automatic

While you have copyright automatically upon making your work manifest, that protection doesn't do much should you need to take action to protect it. In order to file a lawsuit for infringement of your copyrighted work, that work needs to be registered with the U.S. Copyright Office. Having your work registered with the provides a definitive public record that will be accepted in court should the matter go that far. While you might not be overly enthusiastic about the possibility of having to go to court, the threat of legal action can serve to keep at least some potential infringement at bay.

The kind of thing we are talking about here is closer to unspoken "gentlemen's" agreements not to overtly copy certain aspects of apps, which is of course especially meaningless if people are trying to make money. I have definitely seen a watchface in the store which blatantly copied the unique graphic design of someone else's data field without even giving credit to the data field's author, or the original designer (who was credited by the data field's author).

(I do think I would be annoyed if someone cloned one of my non-trivial apps -- "luckily" they're so niche that nobody has bothered to do so. I do have a niche app which uses the same basic idea as two other dev's apps, and I did give credit to them, but I doubt they care.)

Then again, imitation is the sincerest form of flattery.

flowstate said:

I'm not a lawyer, but I think automatic copyright is meaningless unless steps are taken to establish / defend it.

Yes. That’s also pretty much true for everything (not just copyright).

_MASHAKE_  Not sure you are owning the concept of having a trial period in an app.  That's a pretty bold statement.

While you are correct, this sucks when it happens. I feel your pain, MASHAKE

Trial Period is not a concept he's referring to as "his". He's referring to the verbatim copying of the wordings used and the like