I've enclosed a letter with my will - and the executors have copies of both - and the other kids know such a thing exists - so I'm pretty sure that my stash won't be trashed. Having said that though, I'm also actively purging everything - and sharing with my DD's and DGD who have expressed interest. There may even be a bit of a war over the machine they learned to sew on!
But we have lots of fun when I'm purging and they are there!
And they know I "will" come back to haunt them....