With the magic system, how do you think one would handle creating a ward or seal?
For example, assume the caster creates a ward that puts whoever encounters the ward to sleep. The skill check aspect is easy to figure out (opposed check of the victim's skill vs. the warder's magic skill), but creating, applying, and sustaining it is the question.
Most settings that use these kinds of wards have them be physically applied, like with a painted rune, carving, or paper tag, and don't require the user to constantly sustain them. In Star Wars, laying traps often isn't a skill check, just an action.