This. Although I'm on Verizon, this seems to be the case from multiple reports/folks. From Verizon corporate stores, you have to have a Verizon account, though I'm not sure if anyone was lucky enough to purchase one from an authorized retailer store and just walk out.
Otherwise, if you can acquire one from any other place, just swap out the sim card and you're good. You might be able to go through someone who has a Verizon account, and then have them order one. You'd pay them for the phone, or use your credit card for the charge. Chances are the Pixel you want is out of stock though, so you could just join the Google waiting list, or wait for the "exclusivity" to drop.