I’ve flown with Air Asia a few times and with other airlines that have hand luggage weight limits.
I’ve never had my bag weighed by Air Asia, though I have seen others go through this. It does sometimes happen.
My impression is that I’d say it really depends on two factors.
1: How full the plane is. If they are expecting a packed flight then they will be very actively looking for luggage to force into the hold.
2: How big and heavy your bag looks. If you have a small handbag containing a 30kg weight and are strong enough to carry it as if it is nothing than you are much less likely to be caught out than somebody with a huge rucksack that they're struggling to carry but is just narrowly over the weight limit.
The general I’d advice I’d say is to prepare for the worst and keep your bag around the weight limit. However if it is unavoidable that your bag is heavy then try and hide this fact and make it appear as light as you can; also do your best to stay out of the way of the staff members who are weighing bags!
I'd say this is a case of weighing bags is something they reserve the right to do if they feel like it (e.g. if the plane is full) but isn't their standard practice.
