True story.
About 20 years ago I had an Amex Platinum card, and used it a fair amount. Did not check my account balance on-line and was paying from paper statements.
My ex had a supplementary Amex Gold card, and was using it as her main card, cuz I paid the bills.
When we got divorced I cancelled her card, as our wealth was equal, and she had credit cards of her own.
I switched from Platinum to Gold for my own use, as I couldn't justify the annual cost of the Platinum card for myself.
Anyways, long story short, about a year after I switched from Platinum to Gold I got an email from Amex saying that I had accumulated over 300,000 points on my Platinum card, and they were transferring those points to my Gold card account. That was worth about $1,200 in statement credits.
I was pleasantly surprised to say the least...