My sister-in-law was refused entry yesterday with BD*S on a Tiny fare in DUB. She asked what the bloody point was in having the damn card was. The supervisor replied that she really had no idea any longer and apologised quite a lot. She then went across the hall and used her Priority Pass in the Analivia Lounge.
I am doing a mileage run to JFK on Fri. so will be passing through DUB on a T class special sale Tiny fare. I'll report on how I get on with BD*S and OZ*G. Should give some indication as to the way forward.
row1A, bmi tend not to allow standby, especially not in LHR. They want you to pay a change fee and upgrade to the available fares. However, outside LHR, many have some limited success where the change fee is waved, especially if the passenged is BD*G. I'd say as a UA1K, you haven't a chance, unless your flight is heavily oversold, and the previous flight is light.
Look forward to seeing you in DUB next week!