[quote]downloading it and deleting after 24 hours is not illegal[/quote]
The 24 hour rule is a net myth , it has no basis in the law.
There is no evaluation period unless specifically allowed by the copyright holder
Distributing copyright material without consent of the copyright holder, regardless of how long the down loader keeps it for is illegal.
Downloading copyright material without the consent of the copyright holder is also illegal. There is simply no getting around it.
The "24 hour rule" is a clear example of why you should never take legal advice from software pirates. There is no such rule; downloading a copy of copyrighted software not intended for distribution is always illegal, no matter how long you have it.
[quote]downloading it as a backup for games you alreadyhave is not illegal[/quote]
Yes it is illegal,
Even if you own the original game, you are not entitled to download a copy of it. Copyright law clearly states that the only copy of software you are entitled to is the one you make yourself.
Before posting things you don't fully know do a little research first, its easy,
use Google :P