Ya know...that is a very grey area. While 'Fair Use' rights in the copyright laws allow for a functional backup, It is a two edged sword. While some would use it for it's intentions...you have some who would also use it for piracy means.
Copy-protection schemes really make it hard for the 'average' user to make copies.
Example: You own a copy of Final Fantasy XII. You would really like to back it up because you have a kid who manages to get into your games even if you put thems omewhere out of reach. You go online, download the ISO througha torrent, and your internet gets shut-off...seems liek someone reported you as violating some law. You have to call the ISP to reinstate your service under the 'promise' you deleted the offending content. You don't. You begin to do this for ebvery game you have. You end up getting caught again. You got caught so many times, the ISP does not reinstate your service, and you are also reported lcoally to other ISPs and also run the chance of getting into some lawsuit by the copyright holder. Each time, noone, not event he ISP asks you to come down to their office and show them you own the game...
In essence until better distribution capabilities come along or everyone cools their jets about it; you'd be better of just building an ISO on your own. There are many freeware and paid programs (even with full use trials) you can find that would let you make a 99% good backup.
Avoid the headache and do it yourself.
((Yes...this si from personal experience