We have a moral obligation to contribute to the organisation that provides somewhere for us to play. Normally we play in a pub, and contribute to them by drinking their beer, possibly buying food there, and hopefully attracting an audience of more paying customers.
If the festival organisers don't want us enough to ask around and find where musicians may be welcome, why do we owe them anything?
Do they think that because we ask for nothing (except somewhere to play) we're worth nothing?

Do you think we travel long distances and spend several hundred pounds (check accomodation prices in Sidmouth for festival week) just to go to a session?

Would you say that non-musicians who hear about a festival and drive down for the day, spending it in the pubs listening to music are "freeloaders". Or could they just be a potential paying audience for next year?
You, sessionman, didn't actually use the term "freeloaders", you said "hanging on to the festivals coat tails". Perhaps you couild define this a bit more tightly. Do you mean standing outside the flaps of the big tent trying to hear a bit of a bands' performance? I've done that. Try before you buy! Sometimes you buy, sometimes you think "not for me".
Or do you mean the "travelling people" who invariably appear at festivals. Do you think their busking, or face-painting, provides them with an income adequate to buy festival tickets? Just be pleased that the festival attracts a few more customers for them.
Or what are you on about?

It's always sad that a festival has to be cancelled, but it's a sad fact that nobody can be certain how well off they will be in six months time. Personally I would buy workshop tickets in advance (again for Sidmouth) if they were available, but nothing else.

Regarding "led" sessions, a good leader will let the session run itself, just "lifting" it if it starts to falter. The ones that try to be "in charge" still have a bit to learn; but it's quite possible to have a quiet word with them! Of course if they're being paid by the organisers they may feel they need to show they're earning their money.

Blimming heck, this 'asn't 'alf got me in "grumpy old man" mode!