Not that I know of. Depending on who you work for, the company may have a negotiated rate. Also, AAA discounts apply for members. If you are going to be going to the same place, I have found you can negotiate even better rates for you and/or coworkers than the negotiated corporate rate.
We spoke to our team and they would be happy to speak with you about the possibility of establishing corporate negotiated rates at specific Marriott hotels in your high volume markets. If you would like to explore the option of corporate pricing on behalf of your company, please contact the Marriott Business Travel Center at 1-800-442-3659 (toll-free in the United States and Canada) or via e-mail at BusinessTravelCenter@marriott.com.
Hope this helps!
Actually it's just the opposite. Rates are higher if you're not staying a weekend day. They know business travellers arrive Sun or Mon and leave on Fri. Giving a discount if you stay on SAT is done to entice non-business travllers.
Having said that, I travel a ton for business but always to the same place. So I was able to negotiate a much better rate based on 150 nights a year or so.