The DeleteAttachment parameter specifies whether to remove attachments from all incoming messages. And this parameter is ignored unless the AutomateProcessing parameter is set to AutoAccept.
I test it in my lab, when I new a meeting request with attachment, the attachement label still appears in the meeting room calendar when I check "delete attachement" or uncheck "delete attachemnt" option.
Microsoft is conducting an online survey to understand your opinion of the Technet Web site. If you choose to participate, the online survey will be presented to you when you leave the Technet Web site.