An email member account question to another hotel chain (Hilton) brought me in reply this email:
We appreciate your e-mail and are dedicated to provide "Best in Class" service by responding to all queries as quickly as possible. We answer all messages in the order in which they are received, with a goal to respond to all inquiries within a 24-48 hour timeframe from receipt of the message. We appreciate your patience and assure you that we will respond to your inquiry just as quickly as possible.
I realize these are formatted and automatically sent but it is nice to know the ball is rolling
I agree. American Airlines has a great program where any comment sent receives an auto response similar to what you described as well as a case #. For me, it an acknowledgment that my email was received, AND, an implied responsibility to get back with me soon. very professional.