It may be that there are far-reaching side effects beyond the immediate issue of passing the hard-earned fruits of one's labour to children.

If it is suggested, hypothetically, that the ability to pass wealth to children is _not_ a material reason for people to work to accumulate it, it may nevertheless be the case that their incentives to work are contingent upon indirect conceptual ligaments of their children's prospective inheritance. For example, they may make certain assumptions about the life their children would be able to lead in connection with - but not exclusively because of - property they may come to possess.

Edit: In addition to possibly removing an incentive, it may even go so far as to create an explicitly negative _disincentive_ for many people--people who believe the government is least morally entitled and least competent to dispose of their money. Like it or not, many people who possess the ability and the inclination to accumulate wealth for themselves through the transaction of commerce of some description feel this way about the government, precisely because the government supports those who lack that ability or desire. Wealthy people feel that that choice is for others to make for themselves (or, if the choice is truly not theirs, gain or suffer from as a consequence of certain natural and inexorable variations in the content of people's lives and the limitations of their abilities and intelligence), but not one that should have repercussions for them and the choices _they_ have made.