I wish they had offered to reimburse me. That is what I had done with my previous projectors I had the warranty on. This time they are ordering the lamp for me. When you put in for reimbursement and they saw how much it cost, they probably changed their policy:). As far as I know, there is no catch. They count on lots of people buying the warranty and either losing the paperwork or never needing to use it.
I think you're right, that many people get these lamp warranties and never collect on them.
For my Sony1000 lamp, I followed their protocol, which was that they would send me the lamp. But they then informed me that their 'supplier' did not have this lamp and that I should get it and be reimbursed.