My understanding is the official policy depends on how much $$$ the WTBTS needs at the time, as they've pointed out how YHWH needs to "remember you" during the resurrection, as all those atoms needed to assemble a human body don't just self-assemble (what: are you an evolutionist?) or grow on trees: someone's got to foot the bill! This is entire basis of the appeal for faithful JWs to share their blessings from God ($$$$) so they are not forgotten or overlooked, but remembered during resurrection for greasing (OK, call it 'anointing') GB's palm as they shed their mortal coil, trying to get JWs to support the org and preaching work via their wills, trusts, etc. It would be a shame to live ones entire life in service to YHWH, and then screw the pooch by leaving ones earthly possessions to your DFed children, right? Why risk the wrath of God at the end?
The society has a pamphlet printed up which explains the scriptural rationale (2 whole scriptures! Sorry, I can't remember which ones, off the top of my head).