For a while now Hoppers were disabled and creeper eggs work some days and stop working on other days. A while ago Hoppers were removed for "duplication" even though it was not a very big problem as it was very difficult and many people did not know how to do this. It is very obvious of the duped items and the players can simply be ban. As for creeper eggs these eggs are very useful for raiding and are necessary in many occasions. Hoppers are useful in many redstoning mechanisms and mob farming like gold farms. This should be fixed as many need these items and will use them if they are enabled.
I had made a thread about hoppers on survival. I support this but would like hoppers on survival as a side note
