MtGox confirmed with me via their support forum they will not refund money to Dwolla users who send it to them. I sent the money even before the rules went into effect and they indicated they would hold on to my money indefinitely, never giving it back, till I identified myself. I actually preferred having a non-verified account because of the withdrawl limits.
Dwolla requires merchants to apply more stringent KYC rules to their customers than they did in the past. You must
have a verified account now if you're using Dwolla. Regardless of whether you sent the money before 25 May, that rule is going to apply to all transactions after that date - such as withdrawals.
It's not even clear that Dwolla is going to continue allowing Bitcoin exchanges to continue using their service - it's rather pointless complaining about MtGox enforcing Dwolla's