Thank you, that is very on-point and correct - I had enabled
privacy.resistFingerprinting! Yes, I think that using the user-defined time zone makes most sense, I thought that was (partly) why I was defining it. Actually, one thing I did to try to solve the issue was to add a location to my event, as before it had none, so I thought it depends on that. Facebook does infer the timezone from the location which was something very confusing in the beginning, because they would use very weird ones when no location was defined (as for online events). But I (and, I presume, most people) got used to it. So, to me, it would make most sense to:
- use the time-zone implied by the event location when it’s defined
- use the user settings time zone when not
- tell the user which time zone is being used, either way and
- ideally, allow organisers to change the time zone manually for each event
This will respect the wishes of those who care about privacy, and give as much control as possible to the event organisers.
Yes, I will create an issue. Thanks again for your help.