substitution for N2..?

Hey I used substitution on the test I did yesterday. It was the correct temperature at 94 and she checked it right in front of me and then she put the tamper stickers on two different bottles of my piss (why would she do a split sample?) The tamper stickers that had my initials went on and now it is sent to the lab. The guy I recieved the piss from only an hour before the piss is completely clean. Is there anyway for the lab to determine that it is substituted? Or with thanks to you have I beat the system, just curious cuz if i get the job i have to buy steel toes and i need to get them soon?

GO buy your shoes!!! The split sample is so that if the sample is deemed adultrated, a second lab can confirm it as adultrated. All DOT test and some non-DOT test are split sample. N2