The general plea here seems to be NO discretion.
However, as a pax it can be very irritating, and appear illogical, when you check teletex and see the flight ETD is advertised as 2 hours late. When turning up at that new publically notified time you are refused carriage; yet the a/c has not yet arrived. When the LCC's try to compare themselves to a flying train, i.e. late and you miss it. it does not seem quite so similar in all cases.
There was one infuriating case, where discretion might have avoided considerable pax frustration.
Flight B booked. At check in told there was 3 hour delay. Trundle off to gate to see EZ a/c arrive. It transpired that this was the earlier flight to my destination, which being 3 hours late causd my following flight on the same route to be 3 hours late. I sat and watched this a/c depart, at what was my booked departure time; then watched it return and eventually deliver me to my destination deep into the night rather than mid-evening. The galling thing was that the earlier flight was only 2/3 full. When I enquired why such inflexibility I was toldthe computer system did not allow for filling up a/c when elayed. Finding and transferring baggage would casue delays and be difficult, and how would those pax who would be offerred transfers be identified. In this day and age of smart tags on bags, boarding numbers, computer systems etc, it would be a doddle to accomplish within a 2 hour delay period. Surely that is what customer service is all about. It is a service industry, but too often the service is that which is easist for the provider and not the customer.
I have often arrived at check in for a publicised delay with no grief. The same has been true of being loaded onto an earlier, delayed flight. I wonder what is so difficult. I appreciate that it might cause congestion at checkin with more pax than expected, but to absolutely refuse carriage on an a/c which has not yet arrived jst because the clock says so seems daft, especially in my case when the check in desks were empty of pax as it was a quiet period.
There are often extenuating cicumstances. The airline reserves the rght to cancel the flight or stuff you about at will, so why not reciprocate when sme common sense discretion can be applied.
To simply quote the rules, as being black & white, and must be y obeyed rigidly is too easy a cop out.