What happens if you don't send damaged phone back with insurance replacement?

My kid dunked my wifes phone about a month ago.  We immediately called the insurance # to order a replacement which was promptly sent once we paid the $50 deductible.  However, at a friends suggestion, we also removed the battery, opened all ports, soaked in isopropyl alcohol, baked at 160 degrees for an hour.  The phone continued working for the next week until the replacement arrived and still works.

So, does anyone know what happens if I keep the "damaged" phone as a backup?  Will I be charged for not sending it back to the insurance co.?  I can't find anything in their fine print and don't want to flat out ask one of their reps.

Thanks in advance.

In my experience, they have put the cost of that phone against my account, which would be credited back when they recieve the phone. 

True that.....sprint screws u royally.....they are like tax collectors.......they want there money lol.  its not worth it send the POS back......

interesting, my A-940 crapped out, so I payed the insurance, got a new one...then they couldn't get it activated...( ends up they tried to activate my wife's phone) anyways they sent me another.  Figuring out what they did, I got the phone they sent activated, then when the other new phone arrived, we activated it under my wife's number...Sent back my crapped out phone, and her screen scratched phone...no charge.

Being honest ( guilt got to me ) I called the number for the replacement, and told them what I did...Surprised When this rep said, " hey, send in any sprint phone, we don't care what phone, as long as it's a sprint phone"...I was like " you gotta be kidding right?", he said " Nope, not kidding"...

So, that seems to be the take on it.  My neighbor had to get one replaced, and he sent back a free phone he got for signing up, and again, no charge.

Edited:  Kind of makes sence, they don't guarantee the phone your going to get will be the same either...something to think about

I told them, on the phone " I'm smashing this #$%^& thing right now, as we speak" and the lady I spoke with said " Oh my...so, what's your credit card number?"
Lost or stolen, I couldn't answer, those are just two instances I can tell about.
Once they did send me another phone from what I had origionally, and I was furious...but then they made sure to read me their policy on getting a phone replaced...

Look, I'm not saying switch phones on the return, I'm only stating a couple of instances that
I experienced/witnessed. 

Does anyone know whats the difference is if your phone is stolen/lost compared to just damaged/broke for the insurance replacement? The reason I took the sprint insurance over the Bestbuy insurance was because she said Sprints covers lost and bestbuys only covers normal damage.

I know for my old Razor phone at Cingular I had insurance on it and left it out in the rain, it broke.  I called them and told them I lost it or it got stolen or told them it was dropped in water, I forgot what I actually did, but when the replacement got here and came with the extra bag to send the other phone back, I never did.  I ended up selling that broken phone on ebay and making like $20.