A key reason a contractor should ensure the person signing a contract has authority to bind the property is that:

解析

Signing the wrong person costs the contractor twice. The contract binds only the party who signed, so a tenant, a property manager or one co-owner acting alone can leave the contractor with no claim against the person who owns the property — and the mechanics lien is no rescue, because Civil Code §8444 lets an owner who did not contract for the work record a signed and verified notice of nonresponsibility and take the fee interest out of reach. For a home improvement contract, B&P §7159(d) requires the writing to be signed by the parties to the contract, so who signs is a compliance question as well as a collection one. (b) is backwards: less certainty about who is bound makes a written scope more necessary, not less. (c) and (d) are invented — public works status turns on public funds and a public awarding body, and no signature sets a price.