unrooting question

[I am Fake Jesus]

so my wife bought a nook color. we decided to root an see how it was. she decided shed rather go back to the stock nook. i unrooted it with the process from nook.devs. we have noticed her battery doesnt last very long even before rooting,as every day she is having to charge it. where her friend only charges every 2 days. she was wanting to take it to b&n to see about it....tho i put it back to stock, is there a way for them to tell an void the warranty?

 

[NDchem2014]

Did you make sure the wifi is off? If it's on, the battery goes fast.

They say, once unrooted and stock, there is no way for the store to tell it's ever been rooted.

 

[I am Fake Jesus]

yea, that was one of the first things i showed her how to do since she uses it alot at work where there is no wifi. an he screen brightness is very low. she has discussed it with a friend an there use is about the same

but ok, iv never rooted before this so i wasnt sure. thanks for quick response an help