DISABLED HOPPERS?! REALLY?! WHY??? To stop duping? Do you have any idea the implications from such an act? You're not just stopping the dupers, you're preventing all applications that use hoppers! IRON FARMS, AUTOMATIC FARMS, and that's just off the top of my head! Just disappointing.
They will be enabled eventually till then learn to make your automatic farms semi automatic and learn to put things in your chest manually.
Also, there is a duplication glitch in Survival before, and I'm not sure if it was fixed. The one with the nether portal I think some people were using nether portals to duplicate items...
I'm Neutral on this subject but I would say that the server run good without hoppers. That way people have to make his way to have money and it makes it more difficult. This could be good or bad. xD Anyways people on survival have iron farms you dont really need hoppers that much. :p