My suggestion is a flag which enables adventure mode. Some people have a parkour residence where you can go and parkour but sometimes people will place blocks and get up and it can be very obnoxious. My suggestion is a flag you can enable which disables people from placing blocks, kind of like adventure mode. This flag doesn't necessarily need to be for parkour res' but it can be annoying when people place blocks. This will also be useful for people hosting drop partys and dropping from above. This flag may not be necessary for some people but would be nice for some people.