What to use for access_id on "backend" (non-content) ElggObjects?

I sometimes have a need for "backend" objects that don't provide user-facing content, aren't registered for search, and shouldn't be associated with any particular user. E.g. tasks in a task queue that runs on cron.

Is it safe to give these objects access_id = ACCESS_PUBLIC (instead of ACCESS_PRIVATE)?

This eliminates the need for wrapping elgg_set_ignore_access() around queries, but it makes me think Elgg might expose these in some way.

Thoughts on using ElggObjects on generic backend storage (not as "content")?