Yes! They are legal in a Drill. This is why we have them in the classifier. They are illegal to use in any scenario.
CoF 20. No foot-fault lines may be used on any scenario stage.
From the rulebook page 15.
PP 1. Procedural Error (PE):
A. Adds three (3) seconds per infraction.
B. Is assessed when the competitor does not follow the
procedures set forth in the CoF description or when a
competitor breaks a competition rule. Only one (1) PE is
assessed for each type of infraction in a string of fire. If the
shooter does more than one type of infraction, such as using
the wrong specified hand AND fire an incorrect number of
shots, a separate PE is assessed for each type of infraction.
a. The competitor’s foot touches the ground beyond the
side of the barricade on Stage 3 of the Classifier. One (1)
PE is assessed regardless of the number of shots fired.
Since the Bianchi barricade is listed by name for use in the classifier. It is legal and must be used. If they wanted us to move our feet outside the barricade while slicing the pie on Stage 3 of the classifier they would have just said use a 2'x6' wall. Those that have expressed their concern about the legalities of the use of boards on our barricades, It appears they are legal and proper. (since we only own one Bianchi.)