The specifics about what Guardians do while their kids are sleeping has never really been explored that deeply in the comic yet. I've shown Seth visiting with Persephoni or reading books as Peter is waking up, but for the most part that whole 8-hour block of the overnight shift has been a mystery. It makes sense that Guardians would use their invisibility to their advantage and go check out some fun stuff during downtime after hours.
It almost makes "Night at the Museum" sound potentially like a documentary.
