After recently passing the century mark with no repairs needed, outside of normal w/t maintenance, I called their bluff and won the pot.

Beware of non-OEM extended warrantees. Look for clauses that have something to effect of: "ACME Warranty Co. can use any means deemed necessary, at the sole discretion of ACME Warranty Co. to return the vehicle to good working order."
Is robbing parts off another vehicle acceptable? As long as the vehicle is returned to a "good working order" condition, and they deem it necessary, YES it is.

You'd be pretty po'd if something failed on your pretty X and you end up at Bobby Joe Jr.'s Garage because that's the only ACME authorized repair center in town. Or, even worse, they replace your spent (offroaded) transmission with a used one from the junk yard to get you by until the warranty ends.

As with any contractual agreement, be sure you READ what you're getting, and how you're getting it.