I like your Photo.
As far as a sticky lock. If I bought a knife and it had a sticky lock I would be more than tempted to send it back; assuming we are talking a knife that cost $100 dollars, $200 etc.,
I have been known to take my diamond files to a lock or two to improve the performance. They DEFINITELY were not sticking though. If I just loved the knife to death I would immediately take it apart and get it working. Of course any knife that I was that excited about would be from a maker that could . . . well . . . actually . . . basically speaking . . . MAKE knives so it would not be an issue.
Or maybe I'm over thinking a simple and pleasant thread .