Unfortunately, I don't think any consumer grade tools have an 'unconditional warranty'; misuse, abuse, acts of god, etc, voids the warranty. So, even if the Rigid folks have to verify the battery is defective that's a whole lot better than Ryobi, Craftsman, Skil or some other entry-level manufacturers will do for their batteries - they consider batteries a 'consumable' item and unless it craps out within days of leaving the store, you own it.
You can get great deals (less $$ than Ryobi, et al) on Amazon for Hitachi, Makita and other contractor grade stuff if you have the patience to play the price check game. Some of these prices change multiple times a day for no apparent rhym or reason but you can score big and have a tool that will last you a lifetime (except for the batteries!). Milwaukee has the new lithium batteries that are actually backward compatible with some of their older niCad tools..yet one more variable to be aware of.
-Norm