Cappelletti Overcalled
Assumption:

Your partnership agreement for Capelletti is as outlined on Wikipedia

Absolutely Advancer can pass; the work of interference has been performed. Doing so is a de facto statement by Advancer that he is uninterested in continuing the auction, either because of a paucity of points or lack of fit or both.

The general philosophy is the same for a preemptive opening at the 2-level or higher: the initial bid should be so descriptive that there is no temptation by the initial caller (Intervenor in this case) to continue the auction unilaterally.