As with anything, they have a policy and you should be ready for it to be vigorously enforced.

Now back in the real world...

I find VS very lax when it comes to Hand Baggage. As long as bags look light, I have never had them weighed. I also avoid having the yellow tags put on my rucksack at check-in when possible.

I exercise the right as a Gold to take one extra piece of hand baggage above the cabin allowance, but I am usually flying W or J. Nobody has ever questioned this either on the ground or on board. I have been in Premium with a roller, medium sized tactical rucksack and a suit carrier and nobody batted an eyelid.

As long as you do not turn up with a ridiculous amount of baggage for the cabin, it should be fine.