A buyer or lessee of property for new value who intends (at the time of acquisition) to use the property mainly for personal, domestic or household purposes, takes free of security interests if the market value is $5,000 or less1, unless2
(a) the consumer property in question is serial numbered property. The rule does not protect a buyer/lessee of serial-numbered consumer property.
Motor vehicles have their own extinguishment rules (paragraphs 21.5.1 to 21.7.8). Practically that leaves watercraft since few aircraft cost less than $5,000! This rule offers no protection to buyers of small watercraft valued below $5,000, but realistically few watercraft are priced below $5,000; or
(b) the buyer or lessee has actual or constructive knowledge that the sale or lease would breach the terms of a security agreement granted by the seller/lessor which prohibits the sale or lease.
It is unclear but presumably this extinguishment rule applies only to individuals, given that the property in question must be purchased for personal, domestic or household purposes.
The low value ($5,000) consumer property (except serial numbered property) extinguishment rule will be useful in some circumstances because it extinguishes all (including past or historical) security interests, not just those granted by the immediate seller or lessor.