Interesting, I have never had any issues with it. One of the nice things about mDNS is that the only co-operation you need from your gateway is that it forward

Interesting, I have never had any issues with it. One of the nice things about mDNS is that the only co-operation you need from your gateway is that it forwards multicast correctly which you can usually expect the switch silicon to do. Are you saying that there are many gateways/APs that do not forward multicast according to spec? Or are you using something like IGMP? In that case I agree, there are alot of devices that won't play ball since they don't send JOINs or have other peculiarities.