I'll throw my 2 cents in also. I drilled all the way through, didn't see any reason to go to the trouble of trying to stop. The drill bit supplied with both sets I put on was a bit small (opinion), it took supreme acts of hand strength and cramps to put the screws in. BigLou was there and put in 3-4 screws and will attest to this. When I did the second set I used a cordless drill and went slow to make sure they didn't strip. No loose or stripped screws yet, guards are in good shape (except for lots of scratches).
Very nice quality, fit, finish etc.
FYI the with the smallish hole, I would think you'd be hard pressed to 'accidentally' strip one out during installation.