[simfree]

For TCPA compliance purposes, they should be pulling the deactivated numbers list (which Twilio offers for free), checking the do not call list, and querying the reassigned numbers database to establish safe harbor against TCPA lawsuits.

This is really expensive to do (the RND and Do Not Call lists are very expensive to query, the FCC needs to make these cheaply available) and automation for doing these queries is not offered by most phone providers.