Just a heads-up that may stop some people copping an unwelcome cost.
If you use SecureParking's Secure-a-spot online booking service, they really mean it when they say there's fees for not sticking exactly with booking times - in my case, $39 for leaving 20 minutes EARLY.
I'd have been OK with it if I was leaving late, but $39 for leaving less than 30mins earlier than my best-guess departure time seems excessive.
They also have a silly policy at the other end - if you arrive early they'll not let you in. At all, not even with their additional fees. You just get told the PIN is incorrect (which it isn't - it's just 1 minute too early and they've not put any thought into their error handling). Which is annoying when there's a queue of cars behind you.
They clearly haven't put much thought into their policies. And even less into the website and entrance/exit machine usability - but that's a different issue.
Anyway, watch for those issues if giving them a go.