To answer your question directly, the only technical limitation would be the height of the blast deflector due to landing aircraft, but otherwise there is no technical limitation. Landing aircraft have to land beyond the displaced threshold which is indicated by the arrows. The beginning of the runway is located 500 ft beyond the fence (see google maps photo below), so a 6 to 8 ft tall blast deflector at the fence would pose little risk to landing aircraft, while at the same time deflecting the jet blast from the departing aircraft that are allowed to use the displaced threshold for takeoffs.
They could build a modified jet blast deflector that is no higher than the chain linked fence that separates the airport from the public beach, it would reduce some of the blast that is received at ground level where people are standing. They could make a deflector that is a little shorter than these:
However, this is a pretty big tourist attraction, and there are plenty of warning signs. Its no different than people going on vacations to Yosemite, every year someone slips and falls to their death while walking on a slippery trail to see one of the water falls.