1) Being paid properly or instead "under the table" is irrelevant to the agreement: you are being paid, which means you are receiving "consideration," or a thing of value, in exchange for the agreement. That's all that is necessary to make the agreement binding. Tax violations are a separate issue.2) Your boss could get in trouble for not properly withholding and not documenting your income. You could get in trouble if you did not list all your income on tax returns and pay the appropriate taxes on it, since if you failed to declare or pay taxes on some or all of your income, you violated the tax laws, too.