What do Movie rental Stores do w/ there Bonus feature Discs

[disneyfreak]

I really want Aladdin, and i was considering buying it from my local blockbuster, however, its $20 and im pretty sure it won't get the bonus disc #2 but i want it from a legitable source and i know they are, so if i bought it would it come with it? or what do they really do with those Disc #2s copys ??