I simply use the wire twist-ties that come on packaged bread loaves. They work fine to keep zippers from opening inadvertently.

Golf clubs? They're opened every doggone time I fly with them. But I've never had a problem with anything going missing. The TSA monkeys have, however, broken several of the "stiff-arm" devices I've bought to protect my driver shaft, so now I use a steel crutch I got after hip replacement surgery. They can't break those.