Eigentlich sollte das mal ein Crosspost werden, hat aber wohl nicht geklappt :/
Nächstes Jahr soll das Event wiederholt werden.
I would say it's safe enough if you put it behind a firewall and only publish it via reverse proxy.
That's my way of using it, even though in my case it's behind a raspi in my home network, but it is still accessible from the internet for everyone knowing the URL.
Nevertheless I can't prove it's safety, because this is just the way of using it which a good friend recommended to me. But he is a true expert in field of internet security, so I trust him in this area.
Ar***loch