It's called making the most of the marketing tools one has. Back when I was advertising more, I occasionally did the same thing to announce my upcoming weekday availability even if I couldn't play that Fri, Sat, Sun. (I can see with the way the instructions are worded why this might someday be prohibited, as the forum is intended for weekends, but so far the practice has been tolerated.) As long as providers stick to the guidelines on frequency, more power to them for thinking ahead and not wasting one of their 2 allotted promo spots for the week.
But I agree; 7 on Sunday just before the deadline might indeed be a new record.
There was a time when it was a lucrative spot. But these days, at least in Dallas, its the same one or two people over and over and over. Seems it would lose its punch after a while.