What could make a signed listing contract voidable?

A signed listing contract can become voidable when one party, in this case the seller, is not in a competent state to fully understand and agree to the terms of the contract. If the seller is heavily under the influence of alcohol, their ability to comprehend the implications of the contract is compromised. This lack of mental competence can serve as a basis for claiming that the contract is voidable, meaning that the seller can choose to affirm or reject the contract when they are sober and can understand its terms.

In contrast, being under pressure from family does not automatically render the contract voidable, as this pertains to external influence rather than a lack of mental capacity. Similarly, if a broker makes a mistake on the contract, it could potentially lead to issues, but the mistake itself does not necessarily render the contract voidable unless it affects the fundamental agreement between parties. Lastly, if the property was sold before the contract was signed, this indicates that there was an issue with the execution of the contract but does not relate to the mental capacity of the parties involved, thus not establishing grounds for a voidable contract.