In day -to-day living you are always makign judgements on risk - crossing the road in London is a dangerous business and i might be able to walk a mile and use a set of traffic lights.... or I look round and make a judgement and leg it across.
I suspect a lot of computer users do the same thing - I don't click on links I'm unsure about, I don't even download a lot of emails from people I've never heard of or strange ones form friends and family (tho' that is a hard judgement call occasionaly - they're not all on the same planet as the rest of us), I keep my virus checker up to date etc etc. and I back up often.
I wish I could beleive that every organisation out there took even that amount of care of my data but the evidence is a lot of them couldn't give a toss TBH