I have to agree with Repair, I have fry tanks (10 Gallons w/ dividers) and I move my holding females all the time. They won't swallow the fry, try stripping them and you'll find out how hardcore they are about keeping them. Very protective. I don't even bag them, I just net them from one tank into the other. An adult fish can handle a 2-4 degree change in temperature, which is most often more of a difference than your tanks will have unless you keep some in A/C and others in garage or something. I wouldn't suggest doing that with a new fish, floating that bag is important but remember that fish will have TONS more stress coming home from the store than just going 10 feet to another tank.
JMHO, but it works fine for me.
P.S. If anyone wants Melanochromis Chipokee, Bumblebee, Brichardi's, Fancy Guppies, or needs a culture of microworms and you live close by. . . come take some off my hands. I'm in Arlington, Tx