Here’s one theory, although I don’t know if it is the reason for the change:
Someone I know “R” had a bunch of reservations for family and friends in Palm Desert (MRD & DSV) after trading various weeks through II. So they checked into DSV for one of the guests who was to arrive late at night. When the guests arrived and were given the key they could not get into the room. Security came out and discovered that someone else was in the room (Guest2)! The front desk didn’t understand but they had two reservations from II with the same number with two different people reserved in the same room! When Guest2 arrived after R, they had been checked into the room by a different clerk, and given new keys locking out the old. (No idea how the computers allowed this and the manager could not explain.)
Here’s what happened: the week was originally obtained by “R” as a trade through II. He added his MR# to the reservation and it showed up in his MR account, along with a bunch of other reservations for that same week for him and his family, etc. However, he later RE-traded the subject week from DSV into a bigger unit at MRD (and added his MR# to this res) many months prior to arrival. He completely forgot this and just printed out all his confirmations from his MR account. When he arrived in Palm Desert he then checked into all the various rooms (one of which really was no longer his trade because it had been RE-TRADED, but still showed up as a valid reservation in his MR account (and NOT cancelled).
After many calls by the front desk to Marriott and II the following Monday the following was determined to have occurred. Because his MR# had been added to the reservation, when he re-traded the DSV week for MRD, II’s system could not “cancel” the reservation as it was locked to his MR account. For this reason it continued to show as an active reservation in his MR account. However, II’s system showed the DSV week had been traded in for the new week at MRD. Thereafter when Guest 2 traded for the DSV week, II created an identical reservation with Marriott for the new Guest2. “R” felt really stupid for checking into the room but with all the reservations he had, it was an honest mistake. They had plenty of room in other units so his friends were ok.
Everyone at Marriott and II agreed that this should not be allowed to happen but something with Marriott’s software allowed it, and this was related to it being tied to the MR account as described above. (Even through R was not staying in the room, his MR account showed it as an “ongoing” reservation the whole week. Also, it never showed up as a cancelled reservation in his MR account. He did not get credit for the stay nor receive their folio by e-mail, fortunately!) This all happened in mid-June after which it seems the new policy of not adding MR#s to II trades began. Coincidence??