WordPress MU

Is it safe to have these entries deleted?
I'd like to clear those tables out periodically but am not sure if it is safe or not.

AFAIK, those only hold names waiting to be activated.

I thought MU was supposed to clear those names out if they haven't been activated within 48 hours, but I noticed on my local install it wasn't. Unless it doesn't clear it out until someone want to register the same name or something.

On par with this, it might be a nice feature to have the ability to set the time limit for the expiration of accounts waiting activation, and be able to click a button from site admin to clear anything older than the time specified by the admin.

Could be a plugin too, I suppose.

That'd be a great plugin. Wish I had the php expertise to implement something like that.

I wish I had the time to put it together.

It wouldn't be that difficult, really. Just unfortunately for me, what little spare time I've had of late has been stuck into putting together my own MU install.