I think though that this response is predicated on the school's coming from a relatively developed nation.
If the poster is not from one and is talking about getting free internet in locations that don't have it at all for their school I think the answer would be different. Because then it's mainly about the cheapest technology that can get it done, and won't be touched or bothered by anyone because it's not worth it.
The main issue being getting the technology and setting it up. Not talking with the IT department at a school.
Of course there will be some people that the poster should talk to, but I think that hurdle is relatively lower than getting extensive network equipment delivered to places which have underdeveloped infrastructure.
Often, this implies throwing out all of your existing access point hardware in favor of something that supports 802.1X/WPA Enterprise. You also need to build out a Radius authentication backend if you don’t only want to support inbound roaming.
You could say that that’s no worse than providing unencrypted Wi-Fi with a common SSID that people might have configured on their devices as auto-connectable, but I think the perception of Eduroam as being better than that (due to being encrypted) does exist.
To efficiently manage that, Eduroam is set up as a “federation of federations”. To join, you’d have to work with your country’s academic/research network organization (NREN), which are often affiliated with tertiary education institutions. These have very different problem domains than primary or secondary schools. For example, most people eligible to access Eduroam will be adults.