hoser, n.
Someone that "hoses" a shared resource for him/herself. For example, on a multiuser computer system with limited disk space, but without strict disk space quotas, someone who uses a hugely disproportionate amount of space. Or say at a talk with free food, someone who takes a lot of food and leaves some people without food.
Hosers exist everywhere and are the reason that strict, official limits must be imposed on everyone.