In an ideal world, all of our clients would use RFC 2474 DSCP values to mark the QoS/Traffic Class IP header fields in order to voluntarily participate in traff

In an ideal world, all of our clients would use RFC 2474 DSCP values to mark the QoS/Traffic Class IP header fields in order to voluntarily participate in traffic shaping prioritization with ISPs. Exceed your monthly quota at high priority, and all of your traffic gets dropped to base priority. Though, realistically, nobody is properly incentivized to make use of QoS/ToS (except internally to some networks), because ISPs aren't incentivized to implement anything until application developers label traffic, and consumers won't pressure application developers to implement anything until ISPs provide incentives to consumers. Also, OS/API support isn't great at present, and application developers in most cases would just always label traffic as high priority. At least for phone apps, tagging traffic as high priority could be a an app permission that could be flagged/denied to the app at installation time (or later granted/revoked).