What proof might Swiss authorities ask for to confirm I am a genuine cross-border commuter?

Because the G permit depends on you genuinely commuting and returning to your foreign residence at least once per week, Swiss authorities may ask for proof that you actually make these regular trips. Examples of acceptable evidence include train tickets, public transport records, or toll and road receipts showing your cross-border travel. Keeping such records and maintaining a permanent home in the border country helps demonstrate continued eligibility. Failing to meet the return requirement can put your commuter status at risk.