The marking was opt-in because some consumer ISPs/routers bleach or
reject DSCP-tagged packets — but that risk lives on WAN paths, and the
win (APs map DSCP to WMM airtime priority — real for exactly the Wi-Fi
downlink field case) lives on local ones. The default becomes AUTO:
mark toward RFC1918 / ULA / link-local / loopback peers, stay off
toward anything routable.
PUNKTFUNK_DSCP=1 still forces it on everywhere, =0 stays the kill
switch, and the embedder hook (the Android low-latency tie-in) still
forces on regardless of the peer — for paths like VPNs the address
math can't recognize as local. Decision + classifier are pure and
unit-tested; the connected-loopback test covers the AUTO path end to
end. Windows qWAVE mechanics unchanged.