I just brewed a strongly hopped IPA. Took off like crazy, yada yada. 
Nice 2" - 3" of Krausen formed and then eventually fell. But it left an awful lot of Krausen-residue on the sides of the carboy over the wort level. And the airlock wasn't bubbling anymore, which after only 1 week seemed premature.
So! I reckon there is a lot of usable yeast in that caked on krausen... I gently whirlpooled the carboy by rocking the neck a bit and the whirlpooling wort rinsed the majority of that caked on krausen back in.
Within a little while, the airlock was bubbling again.
Anything wrong with this practice?

Nice 2" - 3" of Krausen formed and then eventually fell. But it left an awful lot of Krausen-residue on the sides of the carboy over the wort level. And the airlock wasn't bubbling anymore, which after only 1 week seemed premature.
So! I reckon there is a lot of usable yeast in that caked on krausen... I gently whirlpooled the carboy by rocking the neck a bit and the whirlpooling wort rinsed the majority of that caked on krausen back in.
Within a little while, the airlock was bubbling again.
Anything wrong with this practice?