Yeah, that would leave a bad taste in my mouth too... FWIW, I've done this on my 87, a '73, my 85 Monte (before and after an LS swap), a FWD Saturn, a '91 Toyota Cressida, and a 2013 Yukon without issues, but come to think of it, that Cressida did do something similar once the head gasket leak got worse (I drove it broken a lot longer than I should have, but life didn't slow down long enough to do it right.) Keep it in mind as a backup trick if needed, but that's a valid warning.
Fun tidbit, that Cressida had a cap on the overflow bottle with a built in whistle. When it started boiling over, I heard a tea kettle sound coming from under the hood that grabbed my attention pretty good, better than any idiot light or gauge needle, and didn't require a Body Control Module to run it. There were tons of little features like that, I really hated to sell that one...