Actually Inaris,
back when I used to work for a local retail computer supply store, I spoke with Microsoft for a customer...asking what the deal is.
They told me that if they purchase a software package like Office, they are legally entitled to install it on their desktop computer and laptop computer....not two desktops. They feel that having it installed like that, they are using it for work and work at home. ... not sure if i'm explaining it correctly..its been a long day..