PAHT - Broker issues?

Hello.

We are in the middle of our Tessitura implementation process and my team has had questions come up regarding using PAHT. In past years, we know that brokers had purchased online, created and sold multiple PAHT copies, thus creating issues. We haven't used PAHT much in the last few years as a result, but recognize that most organizations are offering this convenience to their patrons. Reaching out to the Tessitura collective brain.... how have you dealt with PAHT/broker issues?  

Thanks, in advance!

Amy