Some people take advantage of this glitch. If your on an island you don't have permission for you can place a block jump on it and keep stacking the same block, I know its hard to explain............... but you can stack one block on top of another so you can get over a fence on an island you have no permission on buy stacking a block jumping on it and jumping out of a fence before the block disappears because you have no permission, I hate this glitch because people have been getting out of my coops shop. I know this is VERY hard to explain.
I have tons of screenies of people doing this Then they just all of a sudden get on a 2 block high platform xD Yeah I think people will just need to make their boundaries higher to prevent this. Cause this isn't a plugin problem it's just a lag problem. The only way to fix it is to make everyone stop, which will be very hard to do But yes this happens a lot. Especially people complaining in chat.
This isn't particularly a permission problem, but a tiny amount of block lag. You can do the same thing with breaking blocks in protected areas on .NET. There's nothing we or the server owners can do.