Applying gaffers tape to a stage curtain is probably the WORST thing one can do to a drape. My velour is cringing.
Now Derek, You know that is patently not true,
The WORST thing you can do to a stage curtain is stumble into it while carrying a bucket full of bleach, then taking it outside to dry-off, Or maybe the WORST thing you could do is to point a S-4 right in the middle of it at point blank range and cranking that puppy up to 11.
You could bring a 4ft diameter fan on-stage to help dry a floor you just painted, and forget about the slit-mylar rain curtain they just flew in.
I can think of a lot worse things than putting Gaff tape on a curtain.