Do an experiment on the invitation email to show the number of licenses left if they have become scarce

Do an experiment on the invitation email to show the number of licenses left if they have become scarce (perhaps less than 20% left). This may increase the rate that those users who accept the invite.

The text would say something like (for an account with 100 licenses and only 20 left):

There are only 20 licenses out of 100 left on this project.