It says it all really - you forgot.

No need to try to offload your forgetfullness onto BA (or any other organisation).

Like entering in for any offer or competition, if I did not meet the criteria, I would simply expect my application to be binned. I wouldn't expect them to go to the trouble of contacting me to tell me that I was inelligible.

Hence reading the t&c's before I apply for things (or applying later on other's behalf).