I am familiar with this tradition and when I was a kid I do really thought that it is a bad thing and that people should focus more with the mourn and not with activities involving money or gambling to be more specific. As I grow up and learned that it is helping the family in the wake, and yes financially. It also adds "bond" to people who attended the wake in some ways. But there are people who are not having the intention to mourn; they're only visiting the wake because of these activities. Is it a bad thing? Morally, yes however no matter how we look at it, it is indeed legal and with approval from the family of the wake..
Haven't heard of this as it's my first time and it's sounds interesting going by the motive of the organization of such gambling games under the wake. I hope people don't get too excited to wish for more of these wake's because the more the wakes the more loved ones that are lost to death.
On the bright side, the initiative acts as a succor of relief to some of the financial burden surrounding burial rites and it also while under the wake help reduce the grieve of the bereaves as they have people around to play with and forget their sorrows with some euphoria that's lifting from the shock of the loss.
Actually, some people have done this illegally before. But, they will make it look legal in a hardcore way. How? They will take advantage of the less fortunate (poor) families of the deceased to extend the wake they will bite this kind of trick because they need the donation to pay the bills for the burial grounds and other payments.
Others are actually renting dead people so that they continue their gambling activities and there is news that these schemes are being raided by the police because there's really no permit for it although it looks legal outside.
I've lived in the streets and I knew a place before where the gambling game "Sakla" happens every day although it's been a week or more. Most of the time the dead should only be there for a week, but there are times that it takes months and the gamblers are still going there.
Sad but true. Those in these types of businesses are taking advantage of it just because it will look legal and the police would not even look for permits until maybe someone tells them what is happening.