joeluke:
Is that in your considered opinion as an experienced social researcher? Or do you actually have evidence to prove this?
Admittedly, there is evidence to suggest people fill out surveys as if they're pretending someone's watching, but on the scale you're talking about - it usually applies to questions about how they percieve their skills (and there's evidence suggesting that people may often under-rate what they're good at in an attempt to appear 'modest' even in an anonymous survey).
But what you're talking about is people consistently and actively lying about issues that they feel strongly about, which there is absolutely no evidence for as far as I'm aware. Perhaps you do it yourself, but if you do then quite frankly you're a total coward.