@Luke Freeman There isn't anything you can do from a technical perspective to prevent licensees from installing the fonts wherever. This is the nature of fonts - we can't prevent copies from being made. But we'd all go out of business if we name the number of licensed copies in the contract.
As a practical matter, these things usually only get identified as a part of a license enforcement triggered by some other more easily identified violationation.
However, it is still very much worth it to say that the license is not transferable. Otherwise we'd be dramatically weakening the EULA.
Additionally, we've had several license enforcements where the client did exactly what you describe, we identified it by asking as a part of enforcing another clause, and the distribution addendum which was a part of the settlement represented a significant amount.
@Kent Lew you make a strong point but I hesitate to lump December in with summer. The thing about December is that we do always see a jump in traffic in the first half because there are definitely companies that are closing out the fiscal year and need to make purchases. That's a massive contrast to the deadness of summer. If you release in December you will get SOME eyeballs. Plus, you're not likely to be one of many foundries releasing that week/day which definitely sucks. So, less than ideal but not the black hole of July and August. The proximity to January (resulting in a low cost to wait) makes me want to agree with you and put a red X over it but I'm going to stop just short of that.