Original source

In a foot in mouth moment only Apple could manage, someone on their legal team has got a bit carried away when writing the Safari SLA.

2. Permitted License Uses and Restrictions.
This License allows you to install

and use one copy of the Apple Software on a single Apple-labeled computer at a time.

The Apple Software may be used to reproduce materials so long as such use is limited to reproduction of non-copyrighted materials, materials in which you own the copyright, or materials you are authorized or legally permitted to reproduce. This License does not allow the Apple Software to exist on more than one computer at a time, and you may not make the Apple Software available over a network where it could be used by multiple computers at the same time. You may make one copy of the Apple Software in machine-backup copy must include all copyright or other proprietary notices contained on the original.

Ooops.

So all of you (well, both of you) who are using Safari on a PC had better get ready for a knock at the door.

Or not.