I don't think minor field repairs to the blade tip will void your warranty (not in practice anyway). I've seen much worse sent to Leatherman and they fixed/replaced it without a hassle.
Obvious, unreasonable abuse may be another matter -- such as burning the blades on a high-speed grinder and then demanding a replacement. They may well forgive you the first time, even though they're not obligated to.
I don't know if Leatherman tracks returns; they probably do. If you abuse tools outrageously, and constantly demand warranty service, you may get a less friendly reception over time. That's seems only fair (to me).
I don't see why reshaping the blade would void the warranty. Sharpen it enough over the years and you've reshaped it. Besides, those tips are so pointy that it's pretty easy to break off 1/8".
WARNING & DISCLAIMER:
SELECT AND USE OUTDOORS AND SURVIVAL EQUIPMENT, SUPPLIES AND TECHNIQUES AT YOUR OWN RISK. Information posted
on this forum is not reviewed for accuracy and may not be reliable, use at your own risk. Please
review the full WARNING & DISCLAIMER about information on this
site.