I agree about costs.
But a organiser could choose someting Newfangled called....communication, communication and communication....
Be clear and honest. Explain why we the exhibitors pay more than before. I am sure most will understand the rise of costs and also its a income for the organisers..
Also we'd feel appreciated more and not like a cash-cow.
We attended W&P 20 times or so. After the first few years we took a modernish car because travelling was quite a way (Dutch) with the added costs of the Channel Ferry.
But for us it was a holiday and frankly nothing similar in our area. After Corona and the extra hassle due to Brexit it was doubtfull we would have attended in the last few years.