I've frequently seen this behavior of folks anchoring within the mooring field in front of Ivan's. Seems to happen most often later in the day. They show up late, all the moorings are taken, so they drop anchor hoping someone will leave a mooring before dusk.
If only they had been "hoping" and maybe stayed clear of the mooring field. More like they forced the other boats off their moorings. "Hey we'll hole your hull so move along". It was amazing to watch.