You could rotate the tires front to back and see if it goes away. You should answer your question from that. I am guessing if they would have left the alignment alone it would have been fine and they actually have aligned it wrong. One simple alignment test is put the steering wheel straight and then from in front of the car site down the side of the front tires and see if they are nearly parallell to the sides of the car. If one seems out of whack then that is a clue the toe-in is adjusted wrong. From their explanation I am guessing they have some Michelins for sale??

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra