You are quite right. IME there's quite a mix. Ther are some excellently disciplined people out there, as well as an appalling amount of sloppy practice.
Firstly let me apologise in advance for an acronym-heavy post
Under Personal Track Safety (PTS) regulations there is a category of IWA - Individual Working Alone. This is usually someone of advanced experience, like a COSS (Controller of Site Safety). They are allowed to work on the line alone, though obviously they should be
more vigilant than a group protected by a Lookout. What has been described here is shameful but sadly quite common.
My personal bugbear is that according to the rules, mobile phones should not be used by anybody when on or near the line, and yet it's a rarity to see a trackside worker who
isn't on the phone.