Questione giuridica chiave
Whether the cantonal court could require an advance payment of costs in an AI appeal without a formal legal basis
Decisione estratta
No. Article 69(1bis) LAI makes AI appeal proceedings subject to court costs but does not authorize a fee advance or non-payment sanction; the cantonal court lacked a sufficient legal basis.
Motivazione estratta
A fee advance affecting admissibility is not a mere procedural detail; under the legality principle, its possibility and consequences must be set out in formal law. Federal law did not provide such a basis, and cantonal procedural law did not fill the gap.