still veering right after alignment?

alright, i got my tires replaced and supposedly had an alignment done (free with 4 tire purchase)
now, i notice my car sometimes veers right, sometimes stays straight, but most of the time goes right so...
what could be the problem if my alignment is right?
i know i have warped rotors, could they have any bearing on anything?

Yes Rotors can.

Make sure you drive on flat ground to check, most secondary roads "fall" at the sides for water shedding purposes...and you car will always pull right, slightly..

see, that's what i was thinking
the roads are all slightly sloped to the curbs to help keep water off it
i think that may be the reason it sometimes goes right, but when it goes right, it sorta wants to take it anyway
but when i did drive over a nice smooth pavement near a school (we don't have the best roads here) it was straight as an arrow