I think this is similar to what some car dealers are now doing like offering free oil changes and other service for life.
The catch is from what I have seen is you must have all regular scheduled maintence items performed at their facility at their prices.
It seems to be a way for them to guarantee revenue in the future at least on scheduled maintence items. Which can be very high at their cost.
I guess if you think about it, if you are paying them for all scheduled maintence, why wouldn't they warrantee it?
Catch 22 to make you think your getting something for nothing.