This is really the wrong subforum for this, but...
It looks like the answer is "maybe."
from the
Preclearance Act:
Right of traveller to leave preclearance area
10. (1) Every traveller has the right, at any stage of the preclearance process, to leave a preclearance area without departing for the United States, unless a preclearance officer informs the traveller that the officer suspects on reasonable grounds that the traveller has committed an offence under section 33 or 34.
...
False or deceptive statements
33. (1) Every person who makes an oral or written statement to a preclearance officer with respect to the preclearance of the person or any goods for entry into the United States that the person knows to be false or deceptive or to contain information that the person knows is false or deceptive is guilty of an offence punishable on summary conviction and liable to a maximum fine of $5,000.
No imprisonment on default of payment of fine
(2) Notwithstanding subsection 787(2) of the Criminal Code, a term of imprisonment may not be imposed for default of payment of a fine imposed under subsection (1).
No criminal record
(3) An offence under subsection (1) does not constitute an offence for the purposes of the Criminal Records Act.
Obstruction of officer
34. Every person who resists or wilfully obstructs a preclearance officer or a Canadian officer in the execution of the officer’s duty or any person lawfully acting in aid of such an officer
(a) is guilty of an indictable offence and liable to imprisonment for a term of not more than two years; or
(b) is guilty of an offence punishable on summary conviction.