BEFORE any money swaps hands or you verbally agree to purchase the Bolt,
just in case you may have overlooked it:
1) meet at a VZW corporate store
2) have a sales rep confirm the ESN is clean (no bills owed on the account presently owning the phone) (this will negate the phone call to provide the IMEI)
3) confirm the SIM card works in the slot (it might work in your phone, but their SIM tray might be jacked up & need repair)
4) confirm the water damage indicator is not removed & there is no evidence of tampering
i believe you must confirm the phone isn't tied to another person's account before you swap the SIM to enable your account on the device.
for all you know, this other person hasn't deactivated the phone from his/her account--you buy it--never see the person again and you aren't able to use the phone.
could be wrong--please feel free to correct if so.