I started this thread thinking that merely a longer hitch pin would be a good solution. It turns out, this is not as simple a question as I expected.
I found a video from a guy whose company had lost several trailers while towing using standard hitch pins. https://www.youtube.com/watch?v=ubP0bsXZju8 I’d never heard anyone mention the need to change hairpins frequently. He thought the swivel hitch pin might be a better design.
But, I found a video that makes me very hesitant to consider a swivel hitch pin: https://www.youtube.com/watch?v=g0ZL_FdOs5U.
I decided to confirm my suspicion that trailer theft was not really an issue. I ended up confirming I was wrong – not an everyday occurrence, but more prevalent than I’d thought. So, a receiver locking pin seemed like a good idea.
I looked for reviews on the Trimax locking pin. That showed up a video that seemed to show that the Trimax locking pin (at least the model shown) was extremely easy to pick. Hmmm. https://www.youtube.com/watch?v=ODFzvS-YRt0
So what locking pin was secure? I searched on “hitch lock picked” and I was surprised by how many YouTube videos showed it easy to pick locking pins. One was even titled “How to steal a locked tow hitch in 2 seconds.” https://www.youtube.com/watch?v=9CdFgFBdU5U
I’d hoped to find a locking pin that was unable to be defeated very quickly. So far I haven’t, though I can’t say for certain there’s not one. For now, I’m back to thinking that I should refocus back on ease of use – whether longer hitch pin or locking pin – and not pay too much attention to security.