The issue they have is retaining control over Samsung whilst having to pay inheritance tax. This is why the stock price rose significantly when Lee actually "died", he obviously legally died before that point the coverup was to maintain control over Samsung, because it looks like they have finally lost control.

So yes, these laws are taken pretty seriously.

Btw, the thing about the gift is true in most countries. The reason why should be obvious: if you could just gift before someone dies then no-one would pay inheritance tax. It is usually a few years: so if you receive a gift and the granter dies within a few years then it is subject to inheritance tax.