I have setup BulkVS for testing, and put as the outbound caller ID a number (main office number) that is with Vitelity, instead of the DID that I got from BulkVS. When I place an outbound call to my cell on Verizon, my cell phone detects it as potential spam. Is there a way to keep the main number at Vitelity but use BulkVS for outbound calls without looking like a scammer?
Most cell phone companies are providing spam detection services free of charge nowadays. They get those numbers checked by a third party as they come into their switch. For instance nomorobo offers such a spam detection service that I use in the USA for all my land lines. On mobile devices you can buy a monthly subscription and the app checks your incoming calls against their database. There are several companies offering the service.
With the proliferation of spam on cell phones and subscribers requesting for compensation for such nuisance calls (because they are actually entitled to as the paying party), the major cell companies started to offer the service free of charge. Moreover they don't even do it at your smartphone's app level, but directly off of their incoming call switch(es).
When you get a call mis-classified as spam, you need to call your provider and ask them to untag the number.
Verizon does it no questions asked, most of its MVNO's like pagepluscellular and tracphone do it too.
BulkVS also makes adjustments if you run into the same situation with a caller that you know to be legit and comes across as a spammer through their CNAM mitigation platform.
For instance a few weeks ago we got our primary care physician's appointment reminder service blocked as a robocaller. Dropped a word to BulkVS, they removed it right away from their CNAM mitigation system.
PS: So, this actually has nothing to do with SHAKEN/STIR or anything such. Termination trunk providers, especially the wholesale ones do and have to allow user provided caller id. As calls are switched from network to network all participants need to honor caller id information forwarding as there is no technical way or authority to determine which caller id is legitimate, which one is not. The FCC rules which predate the voip era require that any and all network provider or transfer agent pass through caller ids.