Not sure about the laws.
I will surely provide the source code after a while so anyone can do an anomymous seedbox like this. otoh, it's not that easy to set up... you have to get the torrent service (I am using transmission-remote) and the tor hidden service running
I think the risk is comparable with running Tor relay.
Imagine someone creates a torrent containing child pornography (of course taking the most extreme example) and uploads it to your server - YOU will be responsible for being the initial seeder of this torrent. I don't believe the laws in the Czech Republic will care that you tell them "oh, but it ain't my data - somebody anonymous uploaded it to my server". You still are seeding it to others.