The unplanned sex videosbest kind of reaction video is an accidental one.

John Hart visited the Sandia Peak Tramway in Albuquerque, New Mexico last month with his grandson and grandson's girlfriend. On the tram ride up, they befriended another couple, and Hart cracked a joke about how perfect a proposal spot the peak would be.

"I said, ‘Wow, hey, this would be a great chance for you to propose to your girlfriend,’ and that put a big smile on her face, and unbeknownst to me, that was the plan,” Hart told local news station KOB 4.

When they reached the peak, the future groom handed his phone to Hart to capture the proposal. Hart, a former Navy photographer, was confident he was up to the task. Unfortunately, he was foiled by the phone's selfie mode.

“I thought I could handle this,” Hart said. “Well, unbeknownst to me, I was taping myself.”

Based on his considerable off-camera laughter, the guy who popped the question didn't seem to mind.

Sure, we don't know what the proposal looked like, but based on Hart's glowing smile and the roaring cheers we assume it went off without a hitch.

Probably best if Hart doesn't record the ceremony, though.