We have an Exchange 2007 user with a Droid X phone who reports sometimes he can't accept meeting invitations from his phone. Come to find out, he is listed as the Organizer of the meeting (which is why his phone wont let him accept it).
How could he be taking ownership of meetings? Wether it's happening on his Outlook 2010 client, or Motorola's notoriously buggy Exchange Active Sync stack code... Shouldn't Exchange permissions prevent this from being possible?