Good logic, bad logic

The world sadly to say is still full of poor logic and poorly argued decisions. ID Cards, NHS computers, the Millenium Dome etc. are excused with shoddy logic and opinions with little or no backup information. Sometimes some faux data is used to backup an argument when the weakness is more than obvious to the casual observer. For instance, a recent survey of Teaching Assistants said that a high percentage of them were expected to carry out tasks they were not trained for such as medical work. The number of respondents was 150 so already the data is weakly representative unless it can be considered a good representation of the population (usually achieved by including both genders across a large part of the country in different schools). However, did anyone else assume that the sort of people likely to fill in the forms are the sort of people who are concerned about something in which case the results are likely to show a high cause of concern.
Another thing I saw today was review of an encrypted USB stick that automatically encrypts everything you write to it in case it gets stolen. The reviewer concluded that because it was so expensive, for a fraction of the price, you could simply encrypt the data yourself and write it to a cheap stick instead. Sadly that is purely an economic argument. Hardware encryption is faster but the key to this argument is that the user does not have to do anything special or run any extra programs etc. If it is used, it is basically foolproof and that is the key to a secure product. You have a DIY job and guaranteed the one time that the user doesn't have time to encrypt the data is when it is lost or stolen and once the data is out, it is out, it cannot be retrieved from the public arena and re-hidden!
I wish people would think more about stuff, be objective and expect people to backup their arguments with good data, then we can concentrate on the parts of the decision which are subjective and not waste time on what should be a no-brainer.