16 CFR § 238.4 - Switch after sale.

No practice should be pursued by an advertiser, in the event of sale of the advertised product, of “unselling” with the intent and purpose of selling other merchandise in its stead. Among acts or practices which will be considered in determining if the initial sale was in good faith, and not a strategem to sell other merchandise, are:

(a) Accepting a deposit for the advertised product, then switching the purchaser to a higher-priced product,

(b) Failure to make delivery of the advertised product within a reasonable time or to make a refund,

(c) Disparagement by acts or words of the advertised product, or the disparagement of the guarantee, credit terms, availability of service, repairs, or in any other respect, in connection with it,

(d) The delivery of the advertised product which is defective, unusable or impractical for the purpose represented or implied in the advertisement. [Guide 4]

Note:

Sales of advertised merchandise. Sales of the advertised merchandise do not preclude the existence of a bait and switch scheme. It has been determined that, on occasions, this is a mere incidental byproduct of the fundamental plan and is intended to provide an aura of legitimacy to the overall operation.