Would a Defrag require testing??

 Hi Everyone,

I am a functional/technical Oracle guy and during our upgrade it was determined we should probably defrag some of the high watermarked tables on Prod before the clone and upgrade. 

I know its probably good to give a quick health check after the defrag but do you think there is ever a need to perform any further testing after a defrag is done on Prod?

Can defragging a table cause issues that would require user testing or is it something that should be seamless to the end users?

Normally I am conservative but I personally think defragging a table shouldnt involve any testing.