If you are referring to the mainland then that's always the risk as the mainland doesn't have any themes really, My region has a theme and I reckon people would for the most part honor the theme (its a blend of cyberpunk, dystopian, and realism - (stuff along the lines of black mirror) and so the builds would be somewhat cohesive and at a minimum be urban/modern
Of course, they'll always be griefers and I'm sure someone at some point will make a tower that looks like a certain appendage but my plan is once the sim is fully ready I'll have some admins/mods making sure that sorta stuff gets dealt with pretty quick
In other news, I'm taking notes because the responses here have been epic and have given me a ton of inspiration