but when they are simply snagging the same thing for the same snag, then that is just being bloody minded.
Not really, but i guess it depends on the safety culture in the company. In "mine" we are required to snag the same thing if it turns up again to create a paper trail that will eventually lead to that problem being solved. If it means to replace an engine so be it.
If something violates the hard limits (like a red line) we have in our documentation we have to write it up, even if it might be permissible according to other (maintenance) documentation. Of course forces higher up the food chain can allways change our documentation to accomodate the facts, in which case we wouldn't write it up any longer (as long as safety isn't compromised). However those changes have to be run by the authority first so normally that isn't done.
Of course they added another reason for us to write every little thing up nowadays, many of which were solved after a little chat with the engineers previously. They outsourced engineering into a different company and now the engineers need the paper to get payed for the work done (and the spares of course, be it only a light bulb in a reading light back in the cabin).