Please tell me Nadi rode in the sidecar and there is photographic evidence.
Even though I have a tuk-tuk and a motorbike, and back in the states I restored, repaired and tuned classic Vespas and Lambrettas, I have never owned a sidecar and it's still a life goal. I've been spying a very skilled aluminum sidecar guy in Thailand on Facebook, and one day when I strike it rich I hope to design a sidecar camper and have it built.
I have never once felt nervous around Khmer cops, but I've always felt uneasy around Thai police and military. They always have their shirts tucked in, wearing boots laced tight instead of flip-flops, and there was always a feeling that these guys take their jobs seriously and won't risk it all for $20 like many would here. From the stories I've heard too it sounds like hit and miss there with the cops, and in your case sounds like a best case scenario.