My friend has found this...

When she uses the /summon command or /give command her world crashes?? And it doesn't save the world which is unfair as she was using cheats on in the end and her sword broke so she did /give <name> <item> (happens with any item) and then her world crashed and was deleted, is this part of the code to prevent cheating or something?? Then in creative she typed /summon <mob> (works with any) as she wanted to show me the giant, and the same thing happened... Please help... this is what I find annoying about minecraft, all these bugs, but hey, nothing's perfect. (Oh yeah, I then watched a YouTube video of giants, nice addition, maybe you could make them spawn naturally too?? And another boss, I've defeated ender dragon loads)