It would be helpful to know the following buckets:

1. How many Cast sinks advertise the canonical Cast receiver device description URL
2. How many non-Cast sinks advertise it
3. How many Cast sinks advertise a non-canonical URL
4. Everything else

If buckets #1 is proportionally very high relative to #2 and #3, then we can target Cast-via-DIAL discovery to only devices in that bucket.

If bucket #2 is high, we can lower it eventually by modifying Cast to advertise a more unlikely URL.

By "Cast Sink" I mean devices that Chrome can successfully connect via Cast channel.