[hinkley]

This is probably a gap in my knowledge, but I hope this isn't a terribly obvious question.

So let's say I buy a bunch of bitcoins and I just sit on them.

A year or two from now, they're worth a bunch of money, so I use them or sell them. How does everyone with the truncated blockchain know that the bitcoins I'm using aren't being double-spent?

[buzzdenver]

The truncated blockchain would contain at least the latest amounts for any wallets. Truncation loses the old transactions, but cannot exclude any wallets that have any BC in them.