Progress is already being made in this area... A commercial stand-alone version of CoovaAAA is in the works. We are also committed in keeping the free CoovaAAA service up and running. As such, we will have to review the usage policy and load of the servers.
I'm thinking that perhaps you are considering restricting free CoovaAAA to non-commercial use.
If so you might consider implementing a feature that would permit the user of an "access code" to view both their usage details and a summary of the account overall usage details. This would assist them determining whether the account is being used for commercial purposes.