Not knowing every single Marriott Rewards member I can't say that speculative award booking doesn't occur, but I seriously doubt it's a major problem or Marriott would have axed it a long time ago.

Being able to book w/o having the points at the time of booking has been a competitive advantage for Marriott over the other programs & quite beneficial to MR members. Hopefully it will survive post-merger. I don't often take advantage of it, but it has come in handy a few times for stays at popular properties that book months in advance when I didn't have the points at time of booking but I knew I'd have the points by time of stay. I don't make speculative bookings.

Example, being a voting member of BAFTA (British Oscars for the Yanks reading this), I often attend the BAFTA Awards in London in February. The governors ball post-awards is held at Grosvenor House/JW. GH/JW often gets booked for hotel awards, so I'll snag the stay award several months in advance (even if short points) because I know from experience that award availability just before the BAFTAs usually isn't available (and I'll have the points needed by then). I would imagine that those who book awards for such big nights as New Years Eve in some locales worldwide, Kentucky Derby, Super Bowl, World Cup, Olympics, do similar. Award availability might be available several months in advance but not just before the events, so the ability to book if short points can come in handy.

As Jon says, hopefully common sense and general courtesy will continue to prevail & Marriott will keep this feature/benefit.

Cheers.