Originally Posted by craigthemif

If you paid cash, you are entitled to 75% of the cash fare as a refund. I believe you can also insist on flying the next available UC, and receive EU261 compensation for the delay. If this involves off-loading and delaying a family, the airline will probably find somebody else to downgrade...

If you paid with miles, you generally are only entitled to 75% of the miles spent (and theoretically the same 75% of taxes/surcharges), although I've seen far more examples of this happening with Avios than with VS - there are some arguments that you should receive the 75% of the cash price, even though you paid with miles. In practice you might want to grab the 100K miles on offer rather than risk losing an EU261 fight.

Although the customer might like 100K miles, VS are actually the big winners, since in the future you will likely be paying them more surcharges for the reward flight, whereas a downgrade should involve a cash refund today...

On another thread a free return flight anywhere in UC was also offered. That may be an interesting option to ask for, especially if you really just want to be on the flight you booked.

That said, I'm not an expert on EU261 regulations. But aiming for cash instead of jumping on an offer of miles is:

1. likely to result in an improved offer
2. incentivise VS to find somebody else to downgrade