Certified cheques can be countereited. just because he's there when you deposit it, doesn't mean it's a legit cheque. I work for a major bank in commercial banking. Dealing with fraud's is one part of my job.
easy peasy.
My wife works for an insurance company and people copy their claim payout checks on a regular basis. Scam goes like this:
Someone shows up to buy your car and you're happy because they agree to pay your over optimistic price. They are just waiting for an insurance claim check to come in but there's another problem. Someone stole their ID and compromised their bank account and the bank isn't releasing any money until things get straigtened out.
BUT there's another way. They will get the insurance company to make the check out to you and the check doesn't even need to be certified. HOWEVER there is a catch. Your car is selling for $4,000 and the check is for $10,000. All you have to do is write them a check for the $6,000 difference.
You write the check. They cash it immediately. They never come back because they didn't want the car, bike, whatever in the first place. That was the smoke and mirrors. The insurance check comes back as counterfeit and your bank negates the $10,000 deposit. You've been scammed for $6,000.
The new security features on checks make them harder to fake but not impossible. The scams are a very small part of the number of legitimate transactions but if it happens to you the statistical ratios don't mean much.
How many people know what to look for on a check in the way of security features?
