To answer your question technically once you were a graduate you were allowed to come and go as you pleased however, out of consideration for others if you wanted to go on vacation or needed to take a trip you should have informed staff so they would know what was going on. The Seed was considered one big family or I guess kind the mindset similar of that of a small town.
The Seed was always careful of how people were doing not only newcomers but also that of the old timers for several reasons. Mainly to do that first: the group was the key instrument in helping people get straight so everyone had to be very aware of their behavior and actions. The second reason was that everyone at the Seed had a past and it was important to make sure no one would fall thru the cracks. (Some Posts suggest that some people did indeed fall thru the cracks), by this I mean that even long timers could be susceptible to depression, envy, jealousy and any other number of human faults you could think of. What emphasizes this was a rule (If you see or hear of anyone with a problem report it to staff immediately and don't assume its been taking care of). This rule can be interpreted in many different ways but that was the reason and origin for this rule.
As per functions related to the Seed nothing was written in stone that you had to go but since it was such a tightly knit group people went and were happy to go. Keep in mind I'm talking about the early 80's thru the 90's when there was not thousands of teenage kids at the Seed all the people made the choice to be there.. Most people left the Seed once they graduated
The Seed was a secular program due to the fact that no one wanted to have a religious affiliation toward any particular religion. the people at the Seed were from various different religions and it was considered counter productive to exclude someone just because of their particular religion.
I heard Art say on many occasions that the most important thing was to develop your spirituality and then you could decide what religion you would choose to follow, (If any at all). As you will see many will disagree with my assessment of this point and they will state their reasons.
Keep in mind these were the technical aspects or outside aspects of how things were viewed. There was, as in any human institution underlying currents of ambition, status, rankings in other words, were did you exactly fit in this puzzle and what kind of pull did you have.
Always remember that this is a forum and people with opposing points of view are not only encouraged but also welcomed