Hey guys. I've been wondering about this. I'm making landing pages and have been told all over the I want to build trust by using these "Norton Verified" "McAfee" logos etc etc. What's the legality with this? If I'm promoting a targeted offer, can I just put a relevant "trust" source on top, even if it has nothing to do with it? Like if I'm running an offer targeted to doctors I could put WebMD on my landing page to give it "Credibility". I mean there's no Landing Page approval for the offers I'm running. What's the deal with this? Do you a lot of you do it? Gray hat but somewhat necessary?
You can put nameless security icons, like the padlock logo, and conversion rates will likely rise.
Trust logos are mostly about making people unconsciously comfortable with the legitimacy of the site. They're rarely looked at and thought about directly.
What about putting "Fox News" or "WebMD", relating to targeting purposes. Would that be too far and something that could get you in trouble?
What about government logos to make it seem more legit? ie. putting the CIA | KGB| NSA |MI6 |etc logo?
And is it ok to modify the logo to make it more generic? Especially on mobile banners where the resolution is not that high.
Trying to figure out the fine line between illegal advertising and good aggressive advertising.
When you mean trouble... what does that entail?
I use many of the trust logos on our landers but only when I have actually purchased them for legitimate use. Its simply not worth the hassle otherwise.
I was doing a test once and uploaded the Norton logo before paying for it on that domain, within 24 hours I had a takedown request and a threat of legal action, seems like they have some sort of tracking system or embed the images/ logos in some way to find them quickly. Since then I only use stuff that is paid for.
I do notice a big uplift in conversions by using them, it adds to the credibility of the site in a subconscious way to the buyer, I don't think they know what they mean but if it looks safe then they feel safe.
As other have posted don't ever mess with any of the Authorities, they might not find you straightaway but I wouldn't want to be the one explaining things when they break down your door.
Another idea is to create your own "security" site a la Norton etc and then have your own security badges etc.......this has worked well for me in the past
So something like Security approved .com ( made up) where people can sign up to use your badges (even if no one does) then use these badges across all your own sites.
At the end of the day its all a big marketing scam by the security companies to scare the life out of people so they will buy their services/ badges so why not replicate the same? I just bought a windows laptop for the office and Norton pretty much tells me Im about to get raped, shot and thrown to the sharks every time I log on...but Ill be ok if I buy their security suite 
If you have a limited audience then why not try split testing just the logo images and see which one performs the best.
Take a look at this article which tests various trust logos: http://baymard.com/blog/site-seal-trust
Here's the interesting test result graphic from the article:
