If the toe ( in / out ) was equal. This is an indication that the differential , ( the rear end) is not 100% true to the frame, and so not tracking behind the front wheels. This could be a major problem to correct, requiring frame work or relocating the differential on the springs in the case of rear leaf spring suspension.
Not really a contributor to tail wag as much as dog tracking.
Dog tracking is best viewed when following behind, the coach is not true in it's lane of travel. At it's worst you can see one side of the coach and maybe not be able to see the mirror on the other side.
If your alignment was to correct a handling problem , not for tire wear.
I'd be after the alignment shop, to re-set the front toe in, closer to it's pre-alignment setting, to help the wandering condition.
They didn't put the tire pressure up when they aligned the coach did they ?
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.