2. The first such instance is described in subsection (3). A Under Section 9-407, [Maine cite section 9-1407] a provision in a lease agreement which prohibits the creation or enforcement of a security interest, including sales of lease contracts subject to Article 9 (Sections 9-102(1)(b) and 9-104(f) Section 9-109(a)(3)) [Maine cite section 9-1109, subsection (1), paragraph (c)], or makes it an event of default is generally not enforceable, reflecting the policy of Section 9-406 [Maine cite section 9- 1406] and former Section 9-318(4). However, inasmuch as the creation of a security interest includes the sale of a lease contract, if there are then unperformed duties on the part of the lessor/seller, there could be a delegation of duties in the sale, and, if such a delegation actually takes place and is of a material performance, a provision in a lease agreement prohibiting it or making it an event of default would be enforceable, giving rise to the rights and remedies stated in subsection (5). The statute does not define "material." The parties may set standards to determine its meaning. The term is intended to exclude delegations of matters such as accounting to a professional accountant and the performance of, as opposed to the responsibility for, maintenance duties to a person in the maintenance service industry.

3. For similar reasons, the lessor is entitled to protect its residual interest in the goods by prohibiting anyone but the lessee from possessing or using them. Accordingly, under subsection (3) if there is an actual transfer by the lessee of its right of possession or use of the goods in violation of a provision in the lease agreement, such a provision likewise is enforceable, giving rise to the rights and remedies stated in subsection (5). A transfer of the lessee's right of possession or use of the goods resulting from the enforcement of a security interest granted by the lessee in its leasehold interest is a "transfer by the lessee" under this subsection.

4. Finally, subsection (3) protects against a claim that the creation or enforcement of a security interest in the lessor's interest under the lease contract or in the residual interest is a transfer that materially impairs the prospect of obtaining return performance by, materially changes the duty of, or materially increases the burden or risk imposed on the lessee so as to give rise to the rights and remedies stated in subsection