Do you know this?

Putting something up for sale on an auction website. You arrange to meet the buyer at an MRT station. One of you is inside the fare gate, and the other is outside. For convenience, you pass the item over the fare gate to the buyer, and he passes you the money.

This is some how a common sighting at MRT stations usually downtown, but do you know that you can be fined up to $2000 for doing that? Under SMRT regulations, it is an offence to conduct a business transaction over a fare gate.

So, if transactions are done by both parties in the paid area or the unpaid area are they allowed?