Alice can do this a lot easier by screenshotting a green checkmark and showing that to Bob

In person merchants need to, and easily can, check their own device immediately. In doing so, it can automatically secure the funds permanently against Alice's pullback by withdrawing to a "real" lightning wallet

Hedgehog is more for situations like online payments and zaps where the recipient might not get online for a few days. Once you do it should automatically secure your funds. And if you don't get the money for two weeks I am of the opinion Alice should have an opportunity to recover it