Students struggle all the time, and some find out (even very quickly) that they just don't like coding. We work across the board to just help people figure out what they want to be doing so sure maybe its hustle on our end for a dropout, but now they know right?
I think its a bigger problem for bootcamps that are super intensive, particularly offline. The application process for these really has to include some coding prerequisites or you simply can't quantify someone's interest!
I can't say we haven't considered implementing a set of entry tests to "prove interest", we may still do this.