It's a challenge, but a very well-characterized one that all enterprise-grade access points are built to handle. Lots of access points, with radio power turned

It's a challenge, but a very well-characterized one that all enterprise-grade access points are built to handle. Lots of access points, with radio power turned way down to prevent neighbor interference, and channels selected to avoid overlap with neighboring APs. Shameless plug - my ex-employer Meraki is particularly good at supplying these systems for events, since they have automatic channel-selection and good tooling for selecting power levels, and let you set up configurations at your leisure that the APs will use as soon as they get an internet connection and fetch the configs from Meraki servers.