I just completed a double round trip starting in PNH. My positioning flight was from BKK on Lanmei Airlines arriving 3 hours before the QR departure. I had checked-in to QR's flight and printed my boarding pass from the hotel in Bangkok the night before hoping this would get me through the transit door. Unfortunately, it did not.

When you arrive in PNH, heading toward arrivals there is a side door labeled Transit with a xray and bag search. I thought that would be easy. They looked at my self-printed QR boarding pass, puzzled, and called someone from immigration. He arrived in 5 minutes and told me to wait while he called QRs Station Manager. He handed me the phone while she explained that the transit door was only for passengers with official same-ticket interline connections. Only airport printed boarding passes were allowed through. I asked if she'd be kind enough to send someone up with my official QR boarding pass and she said that's against policy.

End of story: Paid $30 for Visa on Arrival. The VOA sticker takes up a whole passport page which isn't great if you're running low on space. Visa and Immigration lines move pretty fast. Figure an hour at most if a bunch of flights land simultaneously. Then it's a 5 minute walk out of baggage claim to the departures lobby. Leaving Cambodia, the Immigration inspector looked at my passport, asked how long I was in Cambodia and I replied 30 minutes - one dollar per minute. He smiled in sympathy.