I've allways seen swinging as an expensive hobby even before the current financial crisis. Earning a couple of quid an hour more than minimum wage (when I was working) meant priortising what fun I could do. Fuel was the biggest expense £40 would fill the tank and cover approx 300 miles, it now takes double that. Socials could be quite costly depending on where they where held, often requiring overnight accomodation, room share was quite fun at times. If the venue was a club you'd be allowed in as a guest but still have to pay to get in but not have to join and pay rediculous amount as a single gent. Then there's consumables, if your hosting a party do you splash out on catering or get the guests to bring something along. New party outfit, mainly you ladies.
I do think swinging will change, people will look for meets closer to home with people who can accomodate rather than book a hotel. More will choose stop at home and have people over, it costs about the same to have guests as it is to stop in, you still burn leccy and gas. Swingers clubs will suffer from increased costs and decreased members as some will decide it's a luxury they can do without. I don't think it will be the end for swinging but it will become less casual, the internet made swinging so available. People are qoing to want more certainty about potential meets before splashing out.