Those who want first class can pay for it in advance. No airlines outside of North America offer free upgrades to elite members. I have status with two European airlines and have never been offered an automatic free upgrade. However, since they offer it as a benefits I thing United should offer free upgrades at the gate prior to boarding, and perhaps also those with elite status priority in purchasing upgrades and a discount. I once was offered an upgrade to first on AA at the check in kiosk, I would find it perfectly acceptable for AA to offer all elites the same upgrade 24 hours before offering it to me.