$500 via Verizon e-gift card (sent w/in 8 wks). Activation of 4G LTE/5G phone on One Unlimited for iPhone (all lines on account req'd on plan), 5G Do More, 5G Play More or 5G Get More plans req'd. Device must remain active for 45 days. $500 charge back if service cancelled w/in 12 mos or eligibility req's are no longer met. See vzw.com/bring-your-own-device for details.
And actually, they can't even see the phone numbers of the devices that are connecting on their network extender (though they can set a "whitelist" for devices allowed on the network extender if they choose to).