Since my name was mentioned here, I want to be sure my opinion is understood.
I have seen babies do well in small cages or large cages - depends on the snake, cage, hides, temps, etc. MY babies (and those of most breeders) are used to small cages such as plastic shoeboxes. I always advocate setting the new baby up in as similar a way as possible to what it is used to, at least for the first month or two. And then make needed changes in substrate, hides, cage size, etc, slowly, so the little guy won't have to experience all of the changes while he is getting used to a new home.
I would always be at least a little concerned if a baby is out A LOT, exposing itself to the "predators" its instincts tells it to beware of. It is not unusual to spend a lot of time out when presented with a new home, cage, etc. As stated, it has to get used to the new place and discover whether it is escape proof, where new hides are, etc. There is usually a reason for the roaming around, especially if during the day. Could be hunger, thirst, desire for warmer or cooler temps, better hide, who knows? But I would consider extensive diurnal roaming something more to look for a "cure" for than something to be happy about. However, whether the cage is big or small, if it is set up properly, the snake will get used to it in time, and probably go back to nocturnal or crepuscular wanderings, and will come to prefer its "home" over anything else, be it bigger or smaller.
Of course, that explanation applies less to adults than to babies. Although adults also like to hide, many will eventually learn to adapt and realize that there really are no predators here after all. Although adults still are not usually active unless they are hungry, thristy, etc, they may learn to lay out in the open without fear, unlike most babies.
Hope that helps clear up any previous explanations I gave that were not clear.
