I've just discovered another issue with the same-day standby.

The first time I did this, I switched flights prior to checking in for my original flight (while doing OLCI, in fact). I was added to the 1st class standby list automatically, everything worked great.

The next time, I changed flights after checking in for my original one (also online, I simply checked in again and was offered the option to switch flights, and took it). This time, I wasn't automatically added to the first-class standby list. A call to the elite line didn't help, either. I had to get the GA to add me manually. I got the upgrade in the end, so no harm done in this case, but this could easily lead to you missing out on upgrades which you are entitled to according to the rules.

I think the difference may have to do with having checked in for the original flight first, but of course I'm not sure. If this is some kind of systematic glitch, would be good to correct it.