BEP0044 is a standard, nodes are free not to support it. It is for arbitrary data, our traffic is not any different from any other traffic, if we abuse the network we will get rate limited like any other spammed.

That being said we are doing our best to avoid abusing the network, by heavily caching packets with large TTL values.

There is a possibility that nodes might filter out packets that look like DNS, but first they don't have incentive for that, we are not hammering them or costing them much, second that will require a software updated distributed to millions of clients, not very likely, in fact networks like this have the opposite problem: legacy.