Flying out of the international terminals in Australia and NZ are the places where it can be troublesome. QF and Jetstar and NZ pay to have people stand at the AKL and BNE terminals checking/weighing oversize bags, so at those airports bags over the 7kg might be a problem. At AKL, if you're flying out in NZ in C or are top-tier, you can use the premium check-in/channel, where you'll be able to slip through. At BNE, there's no avoiding it. At SYD, I've never seen them weigh bags--they don't even bother to have those agents because the agents are there to weigh the bags just of QF and NZ and not the other carriers. The 7kg limit is an airline restriction for those 2 carriers and not an airport restriction. I've never seen the policy enforced traveling to Australia/NZ, such as at LAX or SFO or HKG, etc.