Key legal question
Whether a cantonal rule requiring a cost contribution for serving a sentence in semi-detention is lawful.
Extracted holding
Yes. Cantonal law may require a contribution to execution costs for semi-detention; federal law and the inter-cantonal concordat did not prohibit it.
Extracted reasoning
Sentence execution is a cantonal matter, limited mainly by equality and arbitrariness. Article 368 StGB leaves cost regulation to the cantons. The concordat contained no contrary rule, so Solothurn law applied.