Security - computerised or otherwise - is about knowing your rights and responsibilities. Don't give away information you shouldn't - and certainly not for a sweet. Hopefully you fall into the 30% of people who wouldn't give away their password for some confectionary, but don't let your guard down either. Sometimes requests for information from more responsible quarters can lead to the same problems.

As an example, I've been talking to a financial advisor this morning, and one of his original requests was for copies of some identification documents - passport, drivers licence, a recent utility bill. This is to comply with the money laundering regulations we have here in the UK.