I guess the questions about atip Ãs still a daily topic.
If you want to play a backup on a burner you've got to hide the atip... always.
If you can make a backup that will work on a burner without hiding atip and the game has sd2.51+ as its protection, than you have a patched disc and these are illegal.
Inside the protection is something like an atip check. If you are using cd-r or cd-rw, than the writer can read the atip. The atip contains things like the brand and the maximum speed at which this disc can be used to write at. If there is such an atip on a disc, this disc has to be a cd-r or cd-rw, thus not an original copy of a game. This is to be bypassed by hiding the atip. Some report to have trouble making backups when this is turned on (because the writer can't determine what brand and such)
Most of the time securom 4.8+ copies play from burners without the need of any atip hiding. This is because copies without patching don't work. (guess these are always illegal)
The patching in the last protection is done by using a bwa file or an mds file, which contain information about the sector density of the disc. The density of the backups is emulated.
As we all know there is no possible way to make 1to1 backup from sd2.51+ or securom4.8+ games, so something has to be emulated to get a backup to work. In case of securom4.8+ the backups are more cripled than the sd2.51+ backups are.
As of sd2.8+ that's a whole different story.