[rsync]

In my experience, the most common safety practice on chairlift (poles) is a double-nut. It's very common to see all through North America - no washer, just two nuts stacked.

I've never inspected them to see if they have indicators painted on, etc. - one would assume they should ...

[dalrympm]

I've also noticed that the nuts go on top. I've always wondered if this was so it was completely obvious if a bolt dropped out (i.e. sunlight coming through the hole).