I actually bought one of the MiniMed brand waist pouches (not as nice as SpiBelt) back when I got my first pump, but never really used it much. I always found that it irritated pump sites anywhere around my waist because it moves up and down when I sit or stand.
Honestly, it’s also a female vanity issue - there are fewer wierd looks for a “lump” in your pocket or on your waistband than floating around under your clothes. 
I actually wanted to do this exact same thing, and had Tandem support tell me my warranty would be voided if I did anything with the pump without training, which I thought was ridiculous.
That is bizarre and would ■■■■ me off. Then again, Tandem didn’t even see fit to respond to a request for a pump when my Medtronic pump broke. After several weeks of no action on the request I switched to asking for a 670. Medtronic shipped me out a loaner in literally 2 HOURS and processed the paperwork for a 670 a few weeks later. Ergo, I’m not a Tandem fan.
That is not anywhere in the warranty, just that it’s voided if you use it contrary to instructions/manual. There is nothing that specifies HOW one has to be trained. I think someone was taking liberties for scare tactics.
that makes a whole lot more sense, Robyn. The internet can be a useful source of info, but OTOH, a huge source of MIS-information. 
I’m dealing with that right now when trying to buy a vehicle. sigh.