A quirk with EC expiration?

I know ECs are supposed to expire after 12 months of no activity on your account. My trip last year was at the end of August. In July of this year, I made a reservation for the end of September, fully expecting my ECs ($76 worth) to go poof by September 1. They did for one day then came back and stayed there for my trip. I am wondering if making the reservation inside of the 12 month window made a difference. I never thought to ask the MLIFE desk clerk about it when I was there.

I stayed at the MGM Grand on a comp offer, if that makes any difference.

 

I think it's possible. I had at least 100,000 if not twice that many Tier Credits I didn't really earn, and the only thing I can attribute them to is deposits for cancelled reservations.

 

^^ EC not TC


OP, yes the reservation was considered "Activity on your account"

 

$4000 deposit?

When you cancel a reservation and they refund your deposit, or if you pay with ECs and they refund your overage from deposit, they revoke the TCs

 

I thought that night be the case. Thanks.

 

What the heck are these people talking about?

 

I know the OP was talking about ECs.

I've had as much as $3k in reservation deposits open at MGM properties for a single trip. I book way in advance and cover every possible combination of potential dates. This is what the spreadsheet for my July trip looked like, I had a total of $3,200+ in refunded deposits:



I ended up with 437,000 TCs this year.

Trip One:
~70,000 TCs from gaming
$800 hotel spend = 20,000 TCs

Trip Two:
~70,000 TCs from gaming
$2,800 hotel spend = 70,000 TCs

That's only 230,000 TCs actually earned.

I'm mainly saying funky unexpected behavior has been observed.

For example, why should simply making a reservation be considered activity enough to preserve ECs?