Just to clarify the reasoning...

Many moons ago we used to allow it, then along comes some dummy who posted his account info and told people it was cool to run carfax checks on it because they had an "Unlimited" account.

The account got run crazy and carfax shut the account down and investigated the activity. This resulted in the one responsible for the account recieving a bill for abou a grand in useage fees since it was considered theft of services according to carfax.

When this happened the decision was made right there that carfax threads or requests for carfax reports would no longer be allowed.

Also be aware that carfax regularly crawls the web looking for instances of these and the VIN when ran can end up in account suspension or extra charges to the account holder. If you read the TOS for carfax you will see that this is covered in it.

Thanks for understanding, if it were up to me I wouldn't care but this is simply a preventative measure the same as piracy threads get shut down.