[Magic] Using ceremonial magic to create an unassailable magical fortress

[Curmudgeon]

Originally Posted by Plane

I took the italicized "willing" to mean the assistants were willing to help, not that the caster had to be willing to accept them.

Originally Posted by evileeyore

Exactly how I run it. Perform a public ritual, take the very real risk that anyone walking by might not want your spell to succeed.

I took the italicized willing as that the assistants definitely couldn't be unwilling, not that the principal caster had to be willing to accept them but I would also hold that you don't get to be an assistant just by getting busy and participating in the ritual. You have to actually be one of the principal caster's assistants and that does mean he has to let you "into" the ceremony/ritual, whether individually, "Bob, would you help me with this?" or generically, "I'm calling on the members of my circle for assistance."

Simple viewing isn't enough to be a spectator, even an opposed one. If you aren't chanting, holding candles or whatever it is the ritual requires of spectators, you aren't a spectator, you're a viewer, and you can't affect it.