This is very cool.

I wonder if there's a way to control routing client side and remove the list of mac addresses. Eg manage DNS for customers (upsell ad blocking!) and CNAME the unifi entry to a customer specific vhost.

Thank you! DNS-based adoption works well for this. You point the unifi hostname at the tenant's subdomain and the Host header handles routing from there. We also have a DHCP Option 43 generator for setups where DNS isn't practical.