Suddenly realizing that "if aspirin won't help with clots", there's no really good reason to force patients to take aspirin forever after the Watchman!

I guess they're just erring on the side of caution in both cases: IN CASE they might help with clots (which do occasionally form after the Watchman) have them take aspirin - even though, they had the procedure to get off anticoagulants!

Likewise, don't encourage clot-vulnerable patients to count on aspirin for significant protection when it only helps REDUCE the risk.

They don't want to be stuck guaranteeing anything, least of all, as a matter of policy (for which they might be held liable).