An officer can ask for cash or a signed guarantee before letting you in, as insurance that you will follow the conditions attached to your entry. The amount is not pulled from the air. It is built from what you can afford, what those conditions actually require of you, and what it would cost the government to find you, detain you, hold a hearing, and remove you if you disappeared.
(1)An officer can require, in respect of a person or group of persons seeking to enter Canada, the payment of a deposit or the posting of a guarantee, or both, to the Minister for compliance with any conditions imposed.
(2)The amount of the deposit or guarantee is fixed by an officer on the basis of (a)the financial resources of the person or group; (b)the obligations that result from the conditions imposed; (c)the costs that would likely be incurred to locate and arrest the person or group, to detain them, to hold an admissibility hearing and to remove them from Canada; and (d)in the case of a guarantee, the costs that would likely be incurred to enforce it.