One of the FTer here who commented about being petty to file LNF for 0.02 difference is also the one who very much think if you don't tip a good amount, then you are petty. Oh well, we are all entitled to our opinion as long as it doesn't offend the other people.
A lot of FTers including myself are money/points sensitive - that's why we are here to exchanging or sharing information about some special promo/code to save $$$$$. I wouldn't have been able to travel the way I do without the help of other FTers for sharing their tips/information.
Back to Marriott LNF, I think Marriott is charging more for their rooms on Marriott.com than other chains. I can often find Hilton/IHG hotel cheaper than a Marriott. So this LNF is to get people who are price sensitive to stay at Marriott.com, I don't believe that Marriott is loosing money from doing that - each room they sell they get revenue - that's why you see a lot of Marriott properties using Priceline to fill up their empty rooms.
When I was staying at a couple of CYs in Europe, I saw big group of bus tourists staying there too - do you think they really pay Marriott's USD 120 per night?
I saw crews in a couple of Marriotts, do you think they pay USD 249 for a night? Please let me know if they do.
All these are called Price Discrimination.