Hotels can't make rewards bookings themselves. All points redemptions must be made through the Hilton website or by calling Central Reservations. That means the hotel would need to find a real Honors account with enough points to make the fraudulent reservation.
Admittedly, it's been some time since I've read a franchise agreement. Still, I would bet a lot of money that fraudulent reservations would be violations that would get a franchise on the fast-track to expulsion from the chain. Due to the fact that this type of scheme creates a "paper" trail with the chain, muzthe42nd's categorization of this as sheer insanity is right on target.
As someone who used to work in hotels, I can say that point redemptions on non-sold-out nights aren't particularly bothersome. Certainly, hotels aren't making money off of most of them (unless the guest is spending money on extras like food and beverage). That said, hotels aren't typically losing money on them, either.
On sold out (or near sold out) nights, the hotel might actually encourage points redemptions because they get reimbursed by the chain at significantly higher rates.
Frankly, if a hotel is going to engage in fraudulent behavior in regard to points redemptions, it will be nights where they are just a few rooms shy of hitting the percentage that triggers the higher reimbursement. It would be easy for a hotel to juice their occupancy by checking in a few ghost rooms. Since hotel systems are walled-off from the chain (because they are technically separate businesses), it would be tough for the chain to catch they type of tomfoolery.
However, from the guest's perspective, that type of scam wouldn't really have a negative consequence.
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TL;DR: Speculative points bookings made by the hotel are a convoluted way to accomplish very little.