It's the day after use of the BMO Harris online banking system was supposed to have been mandatory and it appears that it still redirects you to the Diners Club system to do anything with the card. Most other things in the BMO system say that I don't have access (which makes sense as I don't have any other accounts with them).

Anyway, I was expecting both electronic statements and alerts to be disabled but it looks like I only had to re-opt into the former. I'll try to use my card somewhere soon to make sure that the transaction alerts still work.