Can I just empty water tanks instead of winterizing?

The trouble is that all it will take is one night of sub-freezing temps for more than just a few hours to crack a "T" or a valve. It's maybe a 30 minute process including blowing out the lines with air first. I get the stuff on sale for under $3 a gal, maybe $12 at most for the anti-freeze needed. Cheap insurance. You know your weather better than I do so it's your call.