I currently sell my font on creative market where it is protected by copyright. A client would like to include the font in a trademarked logo but this goes against creative market's licensing. I have two questions; can I allow them to trademark the logo and continue selling my font and should I charge them for trademarking the logo?
Trademarking a logo where a somehow special font is starring makes that font less interesting to other buyers. It can also create a perfect seedbed for future lawsuits. That's why the market wants to prevent using their stuff for logos or at least do not allow trademarking.
Maybe you can sell a little customized version to the logo maker, if you still want your glyphs to be a part of a trademarked business logo.