I have 3 external 1GB sata drives have them through Esata ports and a sata port, I ahve a simple power switch on the power line to them, is it a BAD thing to shut them off when they are all in standby mode?
Just make sure there not Feeding off the 1's and 0's and the silver platter should be just fine. so i would say yes its fine.
That's how most fast-swap drive bays are designed to turn the drives off. So long as you are disconnection ground first, you should be find.