The one thing that jumped out at me is that you mentioned not wanting to inflate business expenses (which is, of course, completely understandably and laudable) but you can always add some personal stays to achieve a MegaBonus threshold. I suspect this is part of what motivates Marriott to select the particular offers they do for each of us--they know our stay patterns and, rather than rewarding us more for the business we already give them, are trying to get us to spend even more time and money at Marriott properties. I've certainly fallen for it before, spending a weekend or two with my family when work stays weren't going to get there so that I could earn the substantial points bonus.