General Discussion

You don't just make a big PR announcement which has no legal, effect, but pretend that it does. At least take the step of educating the public (and maybe even yourself) about why - as a general rule - there is nothing you can do to stop the performances so the public doesn't believe you are doing something that you aren't actually doing.

And, if you really want to prevent Trump from using your works, at a minimum, choose to license them only through a PRO which has a political license exclusion - and use some of your fame and fortune to take the case to court to establish that artists really are entitled to exclude their works from being performed by someone with whom they disagree.

Even more effective, remove your works from being licensed through a PRO.

Or explore other legal avenues to prevent Trump from using your works - pursue a claim under the Lanham act because his use creates a false impression of endorsement, or a right of publicity/persona which prohibit the use of a person's voice, likeness, etc. without their consent.

Sending a cease and desist letter or a press release is all something people without a public voice and financial means may be able to do. But for someone with financial means and media access - it costs literally nothing (compared to the resources these folks have) - AND - has little potential to do anything other than to curry public favor from folks who don't understand how little it actually means.

If it's a moral stand, than back it up. Otherwise it's just words from folks who have the ability to do so much more.