BigButterBean makes some very good points that we can learn from:
- Save those receipts, in a safe place which you can remember where to look.
- Keep a copy of the bike's, and engine's serial number in your wallet, maybe along with a photo too.  Something handy to show a cop.  (Note to self: print small photo of bike.)
- Some police stations in some towns will let you register your bicycle's serial number with them, in case of theft.  They keep it on file.  This is a good thing to ask about.  (I luck out here, because I work in the local City-County Building and cops know me and they know my bike.  And they've heard what I spent on her.)
Having your ducks in a row ahead of time just might make a difference.