SkyDiving, doing it alone can be amusing but when doing it with about 20 other players is a great laugh.
How and when does a Group Skydive start?
Group Skydives start when there are a lot of admins in-game. They announce it and people from all over SA come to the airport to have some fun. Everyone jumps on a set time.
What consequences will befall the people who interrupt the Skydive?
Most likely they will be spawned helpless in air and fall to their deaths. Admins can also torture them in cruel ways if they want to.
What can happen on a Skydive
While in the airplane ready to jump usually people take screenshots and get into a line, then on a set time everybody jumps out and falls to the ground, some people try to rape, rob, flash, piss etc. on people while they are in the air for a laugh. Once everyone has landed usually an admin spawns a bus and a PartyBus is formed, many other activites are started from a group skydive.
Can "normal" players start a Group SKydive?
Yes, they can, but not so many people will come, when an admin announces it more people come, and also without an admin you may end up without a ride home! :P