I agree - there's no way that's visible at the angle you would be approaching down the driveway. I bet it's a reminder to trucks coming away from those doors.
The indication on the ticket is that it's an HTA offence - what's the location?
I think the private property angle is the best one. If a collision occurred, it may be a determining factor with respect to fault, and I was knowingly going the opposite way to the sign I would certainly yield, but I think that sign is just a suggestion, legally.