I'm not apologizing for LinkedIn, with 5400 employees you'd expect them to have people that know the laws.
But, ... Most small businesses don't know the laws. I worked at a company that threatened to doc pay if people didn't show up for "core hours". My understanding though IANAL is that if they did that we'd instantly become non-exempt because docking pay by hours makes us not salaried. They can fire you if you're not doing the job they want but they can't pay based on hours worked as part of the definition of "salaried" is that you set your own hours and get paid a fixed salary. (if someone knows if that's incorrect please correct me)
"ignorance of the law is no excuse for breaking it" is fine an dandy when laws amounted to "don't physically hurt people and don't steal their stuff".
There are so many laws on the books (statutory and administrative) that is is not remotely possible to follow them all. FFS, there are 40,000 words regulating the sale of cheese. Nobody knows how many laws there even are ESTIMATES range up to 300,000 different laws. But nobody knows for sure http://online.wsj.com/news/articles/SB1000142405270230431980...
I'm also going with the thought that it's possible they did attempt to responsibly follow the law; but like many laws it's a complicated mess that almost everyone is in non-compliance without realizing it.
But, ... Most small businesses don't know the laws. I worked at a company that threatened to doc pay if people didn't show up for "core hours". My understanding though IANAL is that if they did that we'd instantly become non-exempt because docking pay by hours makes us not salaried. They can fire you if you're not doing the job they want but they can't pay based on hours worked as part of the definition of "salaried" is that you set your own hours and get paid a fixed salary. (if someone knows if that's incorrect please correct me)