Incidently I've done bank transfers over $5k and never had to fill out paperwork at the time. Most I had was my bank ask me where it came from when withdrawing half of it on a bank draft. A question they didn't ask when I withdrew the other half...

But I've never walked over the border with more than about $5k cash.

I could swear I've seen issues in those TV programs where two people one form have over $10k ... two people sharing an address is interesting though, maybe it's two related (inc by marriage) at the same address?