Securities laws in the United States prohibit trades made with "material non-public information". A 10b5-1 plan is an affirmative defense to insider trading. The basic idea is that before you get access to material non-public information, you decide "I want to buy/sell X shares on the second Tuesday of every month" or similar. Because the trades are made in a way that was determined before you had access to material non-public information, this is not considered insider trading.

(IANAL, this is not legal advice, etc etc)

What if you cancel the planned trades when you learn of some coming news that disadvantages them?

This is a loophole that exists, yes.

10b5-1 plans set up by the company will sometimes have a rule that no changes are allowed for 30 days, which solves the problem. Not sure how widespread this practice is.

There are rules about amending your plans. My company has trading windows (a month or two after earnings, window open for around three weeks) for when people above a certain level are allowed to make trades. Even higher level employees must have a trading plan. You can only modify your trading plan during the trading window and there are restrictions and limits on how you can modify it and if you need permission to modify it.

Or something along those lines, I'm not high enough level to have to deal with the specifics so I only know the generalities I picked up while trying to determine if I needed to care.

You may have to produce your research or justification for modifying your plans, or selling outside of those scheduled plans. Most attorneys and financial experts will strongly advise you to document every minutia around all changes, no matter how innocuous.

Pretty normal. Their lawyers likely said that as long as they reported in (via Form 3 and Form 4) then it would be complaint enough.

So this was still transparency, and its just fodder for reporters to debate about, because without the Form 3 and Form 4 regulation, you would never know.

Cost benefit analysis.

Uh, what? As another comment noted, they possessed "material non-public information" when they traded. Forms 3-5 just disclose the transaction, not the non-public information that we all just learned about.

This doesn't mean they are guilty of insider trading, especially if there is a pattern of recent sales, but it certainly doesn't absolve them. Definitely smarter to hold off on ad hoc trades until all material information goes public -- or go with a scheduled plan.

here are the sells

http://google.brand.edgar-online.com/?sym=EFX

All of the guys in question all own 40,000 more shares than the few thousand they sold. Doesn't mean they weren't insider trading or avoiding losses, its a good defense though.

Selling outside of a predefined schedule is always at risk of some scrutiny, because they always have inside information.

Given the size of these sells, they probably need it to cover a margin call, since its common for people to borrow against their shares. Would suck if thats what it was because its damning for civil and criminal liability and would have been likely necessary for their solvency.

Enjoy

So, does this mean just the transparency via regulatory filings is enough to absolve them of any legal liability?

It means that someone from the SEC should probably be looking into the trades. It would take a court to decide any legal liability, and charges would be the result of such SEC action. Having not reported the transactions in the first place would have likely made the sales less defensible -- good ol' "why were they hiding if they aren't guilty?"