If you buy or sell any cryptocurrency in exchange for your local (fiat) currency, either in person or through an escrowed transaction, you may be subject to laws in your country regarding money laundering or “money exchange businesses”.
Such laws may restrict the size of such transactions, or may impose rules about knowing the identity of the person you are dealing with.

It is your responsibility to know and follow any such "anti-money-laundering" laws that apply in your country. OmniBazaar cannot monitor or track this (or any other) type of marketplace transaction.