That's why they should buy their own copy of the MacOS. I assume they would not want to use a copy of MacOS without buying it. Now, we know you are an apple phanboy and will spout the Apple company line about licensing. However, what Apple says about what you can do with software AFTER you purchase it is not necessarily the word of God. There are all kinds of legal issues, which we have discussed previously, that are, as yet, unsettled. Cloning is going on in Germany as we speak.
In a recent case, the court ruled that Autocad software could be sold on eBay despite Autocad's license, which stated that it was licensed only to the person who they sold it to. Restrictive licenses are not enforceable in all circumstances. Note also that Intel was just sued in several jurisdictions for its anti-competitive practices, MS has been sued for the same, and no longer does many things that it did in the past when it sells its software. Note also that there is a growing backlash against Apple and its questionable practices--for example, this article 5 Classic Apple Marketing Tactics that Lock You In.
People thought there was nothing they could do about Microsoft's questionable business practices with hardware sellers, software bundling, etc., but some people thought of good grounds to put a stop to it, and they won. Apple may face similar challenges to its practices.
Apple's defense is always market-share based. However, it is a fact that companies can violate antitrust and other laws designed to further competition without having to be as big as Microsoft or without being a monopoly. Companies smaller than Microsoft can still commit unfair business practices. Companies smaller than Microsoft might still have licenses that are overbroad or otherwise unenforceable. If you would get your head out of Apple corporate's derriere for a few seconds, the light of such truth might just shine on you.
Apple makes a good software product. If I decide to buy it, I will use it on the hardware of my choice, not necessarily on their overpriced and overhyped machines. When you get me a legal ruling that says I cannot, please let me know. Until then, spouting Apple's questionable license terms does not convince me.
Good hijack of a thread, though.
You suggested that they by "a" copy of OS X and install it on both his G5 and her PC laptop. Using it for more than one installation is not allowed. That is standard throughout the industry and has been upheld multiple times in court. Buying one copy and installing it on multiple computers is illegal. That's piracy. In addition, on all copies of OS X that are sold, the license that is attached to that copy is an UPGRADE license only.
So what if cloning is going on in Germany. Their laws are somewhat different and that will be addressed in the German courts as it is currently in the US courts.
I am not "spouting" the Apple company line. I am stating the law as I, and a lot of other people, understand it.
However, it is a fact that companies can violate antitrust and other laws designed to further competition without having to be as big as Microsoft or without being a monopoly.
That has been ruled on... and Apple cannot be held to be a monopoly on their own products. Judge Alsup tossed those anti-trust allegations out of court. Res Judicata... the thing has been judged.