BA's insistence that its site cannot issue vouchers unless someone requests them, despite much evidence to the contrary, shows they have fallen into the Software Developers' Paradox of Disbelief.
I've been there many times myself: written some software, tested it to within an inch of its life, thought it was perfect and passed it on to the testing people. Within five minutes they've thrown it back at me having found 14 million errors.
The first response is always: that's impossible. Often followed by: there's no way it can do that. Sober thought soon shows that neither of those statements can possibly be true, and deeper investigation always leads to an "oh yeah" moment.
All software developers suffer from The Paradox at some point in their careers. It's genetic; we share about 80% of our DNA with sheep and that's where we get it from. Sheep live in perpetual disbelief. You can see it in their faces.
BA seems to be sticking to their guns a bit longer than most software developers do, but they'll surely recognise they've fallen for The Paradox at some point. Unless of course they already know that and are just fronting it out because they're greedy, unethical and don't fancy paying too many refunds.
Software should be thoroughly tested, but never by the people who wrote it.