Where someone is going to part with £100,000 I fail to see what difference £250 will make, to say it's a drop in the ocean is an understatement. If taking the moral high ground is priority, then you shouldn't even consider applying to a course that asks for so much cash, because even if the assessment was free ... you are still being ripped off by the overpriced training if successful at said assessment day.
The yardstick I use is the old BA Hamble/TEP schemes, this Aer Lingus scheme would, from a distance, appear to come very close to that in terms of affordability.
And for the chance to have the full training and TR paid for, i think not even applying to it because of a small assessment fee is a bit unappreciative of what the company are actually offering.
If you're unsuccessful, then you have nothing to be grateful for. If you're successful, I think the best way to show gratitude is to put in maximum effort whilst working there for a long time.
At least one of the training organisations which charges an "assessment fee" has the walls covered in TVs and canvas paintings of aircraft. They also give out more brochures and free pens then a man could ever need. Those are some of the reasons why I thought the £200+ was poor value.
Back to Aer Lingus scheme, from a distance it looks very good and hopefully other airlines will follow.