Different textclasses warning

[Daniel]

Hi

When a document with a child document with different textclass is 
typeset LyX warns about this. I am wondering why that is since as far as 
I understood the child document does not incorporate any class 
information into the master document. So, is this warning because I 
could have used commands incompatible with the master document, like 
chapter when the master is an article? But then LyX would warn me 
anyway, or? So I am wondering whether I am missing something important 
or whether I could just ignore the warning.

Daniel