This is why I'm surprised there is not some kind of process in place which confirms that online check in passengers actually intended to fly on delayed or canx flights. There must be hundreds of cases where someone has checked in online then at the last minute decided not to bother, or has had multiple flights booked and gone on a different one instead, but remained checked in on another, only for them to then claim compensation for a delayed or canx flight they never even wanted to go on.
Can a pax check-in online prior to paying for the flight? I didn't think so.
So someone is going to pay for several flights, check in online and then not turn up (no show). Doesn't sound profitable to me.