My Paramilitary has developed a bit of vertical blade play (okay, maybe more than a bit) and the amount of play alarmed Garageboy... but since I know that blade play does not affect or indicate lock strength on the Para, I do not mind it at all.
Apparently if a Para does this it is "defective" and that would make it covered under Spyderco warranty. It is just a side effect of wear on the locking mechanism that should not affect the strength of lockup at all, so I would rather keep my Para in my pocket than be without it for awhile to have it fixed. Again, it does not bother me in the least bit, nor should it bother you. (Unless you are picky, which is okay, because I'm really picky about liner locks.) Also, according to STR the amount of wear on the locking mechanism seems to plateau -- that is, it wears for awhile and then it reaches a point where it has worn in enough that it doesn't feel like wearing down any more. From an engineering standpoint this makes sense to me.