I haven't installed a Pergo floor for years. But the last one I did, the instructions didn't require a sealant before putting down the trim. W/O reading today's instructions and warranty, I'll have to take your word for it that it's needed (with a caveat).
Years ago, the floor basically floated freely. I would suspect that, today, if the floor is sealed on the edges, and since it's touted as a floating floor, then as it expands and contracts, the sealant would break / separate / etc.. And I know I wasn't clear in my original post but when I was refering to water getting to the floor, yes, I was refering to the substrate; not the 'surface'. BUT, assuming the floor isn't to be sealed (again, it's been a while since I've done Pergo), IF you were to put Pergo in a laundry room or a bathroom (which, last time I read, could potentially void the warranty), if there'd happen to be a small water leak, it could easily get to the substrate and bingo. The chipboard will swell if enough water gets to it. Try getting Pergo to pay for a replacement!
I guess I / we've beaten this 'subject' up quite a bit. But if you're already familiar with the current Pergo warranty and want to tell me what it says (in regards to this specific post) as far as sealing the edges (or not) and installing it in a room where there's a potential for water damage (and void the warranty), I'd be much obliged if you'd save me the trip to the store. :) If not, one of these days, someone's gonna insist on Pergo and I'll just have to read it.