I have had a few knives that came with stripped screws. It happens sometimes, unfortunately. Glad to hear that you got your screws replaced for free with little hassle.
I have also stripped a few screws out, and a good set of drivers would be completely worthwhile to get. I lucked out and got a HF precision screwdriver set that has properly hardened bits, not had a single issue yet. It only cost me a mere $5, and if a bit strips I can head right up to HF and get it replaced (and they even let you inspect replacements in the store).