Blocking outbound CID over PIR

I was called out to work on a FreePBX system for only the second time ever at a customer in the telemarketing business. They wanted their outgoing caller id to only show up as “Private” on their prospective customers phones. I found they had 23 channels on a single trunk, rather than multiple POTS lines and their service did not respond to *67.
After checking this forum for hints and LOTS of trial and error I got it to work via the following:

Set Outbound CID on trunk to: “” <>

Set each extension Outbound CID to: “hidden” <1-1-1-1>

The result was all calls to both local and long distance numbers show “Private call” on the dialed phone. If somebody has a slicker way to do this, I’m all ears!

In the USA it is illegal to do that.

telemarketing rules state they can not hide or otherwise make false the CID.
even the bill collectors can not do this.

Yes it is illegal…

I will so inform this customer! I didn’t realize that the rules were different for this type of business.

Thanks for the input!