Today I happened across this tweet thread, and boy am I glad that I did.
I now know that when and why Airtable bills for collaborator usage is made clear in the Who counts as a billable collaborator? section of the Billing FAQs, but to expect that new or recently new users (like me) would pre-emptively read and understand that before clicking the innocuously presented Share buttons is not good enough.
It is a fundamental tenet of ‘on-boarding’ for a complex web app that when users first take a step that incurs additional charges they are warned of that consequence before proceeding.
As with other aspects of the Airtable UI, such a warning should be presented until the user chooses ‘Do not show me this warning again’.
As @harrybr tweeted, this needs fixing.