One possible consequence of using a false name in signing a legal contract is that you could be subject to a civil fraud claim in addition to the breach of contract claim by the person that you signed the contract with.From a criminal standpoint, if the conduct that you did resulted in the person who you had the contract with being deprived of things of substantial value, a police report could be made against you where possible criminal charges could be filed.From a legal perspective, you should not be signing contracts under a false name and false pretenses. The results could be quite adverse.