curious compliance code can cripple kiddie's calliope

This is a Baby Einstein Toy. Aside from it's model number (printed on the bottom), I cannot find out anything about it, even from the Baby Einstein website itself. But that's not what this post is about.
This post is about the curious compliance message on the bottom:

This Device complies with Part 15 of the FCC rules. Operation subject to the following two conditions:

1. This device may not cause harmful interference.
2. This device must accept any interference received, including interference that may cause undesired operation

Ok, I can understand why the FCC would want it to not create interference. What I dont understand is why the FCC would forbid it to be interferred with. Seems to me that a lack of shielding in a children's toy would probably come about for economic reasons all by itself. And if someone did want to build a fully shielded toy, well, so what? The toy was made in 2000, so it's not even some wierd post-9/11 rule. I am confused.

By the way, this device is also featured in a post here, which is the kind of thing that'll happen when you combine two blogs into one.

This post got this comment from Anonymous then: "This is strange, I came across your site, because I also am trying to find out information about the baby einstein toy. I purchased it for my son at a second hand children's toy store. He loves it, but I can not find anything about it either."