I agree. There's absolutely no practical reason to run it without suction. I was actually kind of surprised the Sidekick adapter was set up in a way that would allow that other than simplicity for manufacturing purposes. And it does explain the need for yet another switch, making a total of three to actually power up the Sidekick. I actually discovered this 'feature' by accident when I was testing out my newest Sidekick on my Discovery II. I'd hooked everything up and plugged the machine in, not realizing the switch on the adapter was in the 'on' position. Knowing what I know now, I always make sure that switch is turned off when the Sidekick is not in use.
All that said, I did find it handy to be able to power the Sidekick up for a few seconds to listen to it run without the competing sound of the vacuum cleaner when I was trying to identify and isolate the unpleasant noises it was making when I first got it in order to know what to lubricate. I doubt running it like that a time or two for no more than a few seconds did it any harm.
