If you are using the Gold Class cabins without paying for a gold class ticket then you are now likely to be fined 100 dirhams for this offence.
The RTA have tightened up their checks on those people who just scan through the barriers with their silver Nol card and then show a gold one when they are on the Metro, by now scanning all tickets in the gold class cabin to ensure that is the ticket that the fare was paid with.
So, if you travel in the Gold Class cabin then you need to make sure that you have used a gold class nol card to get into the Metro in the first place.