Let me see... A performer needs a specific microphone... Then expects someone else to provide it... Hmmm...

That's not how I work. If I just HAD to have one special microphone I think I'd slip one in my pocket so that I'd be sure of having it when I needed it. (I used to love that old Reslo ribbon mic, gave me a nice deep brown sound.) That's what being a professional is all about.

Otherwise I'd cheerfully accept whatever the sound man has. Most sound men are better than singers at choosing equipment anyway.

I remember one occasion where the sound set up was for a band and it didn't suit a solo performer very well. The poor sound guy, also a volunteer, was working really hard to adjust it, and other performers had been giving him shit trying to tell him how to do his job. I worked with what was there and using a little microphone technique was able to do quite well. I was the only one to thank the guy after and it made his evening.

Which brings us to microphone technique. HOW you use a mic is much more important than which specific mic you are using. Being rude to the sound man doesn't improve your performance one little bit.