Originally Posted by
der_saeufer
The overwhelming majority of providers that say "no VoIP numbers" don't care enough to look up who currently holds the number. They use a list of central office (NPA-NXX) codes to see whose block it came from and call it good.
Whilst this may have been the case years ago, in my experience at least it isn't now. My cell phone number started life as a VOIP number, and my VOIP number started life as a cell-phone number. I've had a number of services refuse to use by VOIP number, but I've never had any that refuse to use my cell number (ie, the one that was originally VOIP).
Looking up these details are incredibly easy and very cheap (well less that 0.1 cents/lookup)