The specific case I'm wondering about is dealing with my Free Spirit character. From the Runner's Companion, page 91, it states:
Each free spirit has a home metaplane. While no longer a permanent address, the spirit still has ties to this home and may travel from astral space to its native metaplane with a Complex Action. It may return to astral space at any point on Earth that it has previously visited with a Complex Action
What were to happen if a fully-enclosed mana barrier had been erected around that location in the meantime? Does travel from the metaplanes to the astral plane happen, essentially, right then and there in that exact spot, thus circumventing the barrier (though then being trapped inside)? And, if that were the case, could an astral entity capable of going to the metaplanes simply escape a mana barrier cage using such methods?