Could be, but a large fairly well respected international company like Seagate would not need individual peoples emails, as their main market is in the bulk sale of their goods and this award scheme is aimed more at individuals than big businesses.
O.K. they may have your address, but on first contact a simple throw away email address will save any spam, and a rubbish bin at home deals with most junk mail
I often use such email addresses for web offers e.t.c. Using a different one for each company if any of them start filling with spam then I know not to deal with that specific company, as they are the only one's that have been given that address.