Why do schools ask if you previously applied to them on OLSAS?

[Peanut Butter]

Are they able to see your past applications?

 

For example, on Westerns OLSAS it says:

 

Previous History at Western University

Have you ever applied to Western University?
If yes, please specify the year you applied and your Western University Student Number.
If no, leave this section blank.

 Required field

 Previous Year Applied (if applicable)    

 Student Number (if applicable)

[LMP]

I think it's mostly so they don't need to generate a new student number and profile for you. Prevents duplicates.