Anyone have damage from blow-only winterizing?

Blowing lines out isn't a problem or any risk, IF, it's done properly.

If you're blowing lines clear at 50psi and you can hear gurgling that tells me that your air line and / or compressor is WAY too small.

At 50psi and with a sufficient VOLUME of air any water in the lines after the initial bulk of water will become aerosol nod the tap will produce a substantial amount of mist for a minute or two.