I expect you are familiar with the admonishment from TV programmes, "Don't try this at home!". What you are watching is for professionals, who know what they are doing, but if you try it, you might make a mess of it, and that is dangerous. If you're watching Mythbusters or Brainiac, making a mess of it might involve some nasty burns at the very least. But what about survey work, surely that's harmless enough? Well, let me share some thoughts with you.