Oh they'll get plenty of support calls still, almost all about wifi issues. They'll be connected to 2.4ghz on an old device, run a speedtest and only get 30 mbps and complain they're not getting 950 mbps on their free connection.
WiFi issues will always cause support calls no matter what isp. The denser the area, the more wifi interference that exists and will drive more calls.
I understand wanting to offer free internet to a small number of entities and residential areas, particularly hotspots. What I don't agree with is free service for every residential home or apartment. It absolutely hurts your business to do this. It's a charity, not a business then. You say it doesn't take any additional resources to support but it absolutely does. You have way more than $300 into an install. You'll also have to hire additional staff sooner because of additional tech support calls from the res side.
Again, it seems nice to be able to do this but most companies don't have idle resources sitting around to give away things for free. We have zero extra time to work for free.