That SHOULD -- I hope -- be self-correcting. If a grid is advertising a whole bunch of land, and people show up trying to use it and can't, those folks aren't likely to come back again -- and will probably spread the word about their disappointment. That would undo any potential marketing benefit of advertising large amounts of land.
For example -- I'll be writing more about this a little later on -- I recently visited a grid that was advertising a large amount of active users. The numbers turned out to be fake, and I'm not only going to write about it, but take their user counts off my stats report for the foreseeable future.