Title says it all!
What does the caged thing over some people's picture mean?
gg2ez
(gg2ez)
#2
The cage represents “jail”. Jailed users have restrictions when it comes to posting on the forums, if they continue to be asshats whilst jailed, they will be banned.
It says it all on the Forum FAQ in General Discussion.
cornJester
(cornJester)
#3
It means they’ve been very naughty and Santa is only bringing them coal trinkets this year.