Back in the 70s when I was framing houses, I found that out. I bought a fe w of the Craftsman line of circular saws intending to use their guarantee, and I did just that. Amazingly, their saws would last about 4 months or so on the job, which was pretty damn good. And at that time, they did indeed honor the lifetime commitment on power tools as well.
But after seeing me in there so many times with worn out saws, the "tool co rral manager" (yes, a real title!) took me aside and ask me what I was doin g to wear out the saws so quick since he was seeing me about every 6 weeks. I told him what I was using them professionally, and he agreed that it di dn't void the warranty. However, with any of the power tools, it was the d iscretion of the store and the tool corral manager to replace after the fir st replacement. Non corded tools, use them up and bring in the remains, no problem. Corded, store discretion.
Who knew?
I could have taken the tools to the other Sears store (remember, no compute rs to track) and fudged my way through, but I figured I had outgrown their tools anyway. It wasn't but a few years later that the "tool corral manage r" told me they quit honoring the lifetime warranty on their power tools, p eriod. It was a combination of things; first, they were losing their marke t and had cheapened the build quality of their tools to the point they had enough trouble honoring a one year warranty, and second, too many people ha d brought in their tools for replacement. Back then, all you needed to do was bring the receipt for the power tools, but all you had to do was bring the non corded tools in.
I am with you on the Ridgid warranty. I like it. Used it with success, so I keep investing in their tools if they have what I want.
Robert