I had to land in Filton the other day on an emergency, got charged no landing fee but had to pay the o/night which was nearly £20!!
But surely that is the whole point of it?
Because of the free landing fee, you got yourself on the ground. You now had more time to think about things, and what your options were.
If you now decided that, having had a chance to check the weather around, and the forecast and think about your options without having to fly the aeroplane at the same time, that it was in fact safe to continue then you could have without any cost to you.
If you concluded that it was unsafe to continue, then the free landing fee had done its job in helping to give you the opportunity to realise that it was unsafe to continue. Why should it also give you free overnight parking when it has already done its job?
I've only had to divert because of weather twice. Both airports were part of the scheme, but didn't offer to waive landing fees, nor did I ask for them to be waived. I was damn glad to have somewhere safe to land
dp