Utilize your financial knowledge, give your answer or opinion to the input question or subject . Answer format is not limited.

If accepting more than $10K in cash for a used boat, should I worry about counterfeiting?
I'd worry more about falsifying documents of sale.  No good reason at all to do that. Detecting counterfeit bills is easy if they're all new bills.  Hold them up to the light and look for the watermark and the numbered tape in the bill.  Refuse any bad ones.