Will (or did) Live Documents copy Microsoft's UI ?

Live Documents , the new office suite rival say in the usability section:

"Live Documents gives you a familiar user interface - that of Microsoft Office - so that there is nothing new to learn. "

Can they realy do that ??

I am no xpert on any copyright laws and I am all for having the copy and paste buttons look the same on all apps.
but can you realy go and say "I have an office suite that is exactly like that of microsoft" and still walk free ??

What do You think ??