I am basing this assumption on the calls from Rand-PAC frequently displayed on my caller ID.
The caller ID indicated the call came from Melissa's cellphone.
Each of these people has their phone number stored there and is caller ID'd when they make reservations.
(CID) A short piece of text transmitted by some telephone systems describing the origin of a call, e.g. the name of the caller. Some telephone handsets can display this. A computer telephony integration system might use it to trigger actions on the callee's computer such as looking up the caller in a database and displaying their details on screen.
There may also be a separate "caller id number" giving the telephone number of the originator of the call.