Tennis-ball baffle damage?

“A friend admonished me about using tennis balls to fluff-up the down during sleepingbag drying (down). That has always been my m.o., and it's approaching the date that I annually wash my two most-used bags. What say?”

“Tennis balls or tennis shoes are what I've always used for fluffy stuff I want to remain fluffy. It works, if it idn't broke don't fix it! What reason did they give?”

“Said that he read somewhere that the tennis balls put too much stress on the interiot baffling system. You end up with clumpy down and lotsa cold spots (he says).”

“?!? Conventional wisdom says always to use tennis balls to keep the fluff. I've never heard to the contrary.”