Question juridique clé
Whether the appeal against the refusal of immigration detention remained admissible despite the respondent's departure from Switzerland
Solution extraite
No. The appellant lacked a current and practical interest because U.________ had already left Switzerland before the appeal was filed.
Motifs extraits
The court held that the general exception for questions of principle did not apply. The case did not raise a recurring legal issue requiring immediate review, and the respondent's departure showed that he had remained available to the authorities.