I think - but I'm not sure - that eBay's user agreement prohibits the filing of class actions.

You may be aware that eBay in Australia imposed a new rule requiring that PayPal be the only source of payment - no checks, no money orders. A government agency enjoined the practice, and eBay has pledged to fight the government (originally they said they would ignore the order, but they changed their mind and will honor it while appealing the ruling). The Australian banking industry has taken a lead role in opposing the eBay policy. Unless a similar industry group in the USA takes on eBay, I suspect individuals will find it too expensive to challenge the new rules.

Many suspect the Australian rule is a test effort before unveiling it in larger markets such as the US.