Leaving possum traps unset

I volunteer with a local project that uses Trapinator possum traps, and have heard advice to leave the traps unset as a way to increase effectiveness. Could anyone explain the rationale behind this?

Specifically, there were two instances: one was to leave a backyard trap unset for the first few days after installation, so that the possums could get used to its presence. The other was about a trap line in a forest park, a contractor suggested leaving the line unset most days (I believe we were to leave them set one day of the week). In both cases, the trap could be checked daily.

The only scenario I’ve been able to dream up is: a possum could learn that food is available from the trigger in an unset but baited trap, and teach that to another possum before it tries on another fateful night when the trap is set.

I guess it helps if the animal is trap shy, but possums are quite inquisitive with new things in their environment, so I don’t think this make much difference?

It can’t hurt and when the bait is being taken, then set it.