Raisins can be lethal. Although the toxicity isn’t the same for all dogs (same with chocolate) so maybe fine maybe not. Some are able to wolf down huge amounts to no ill effect. Some aren’t.
Raisin/grape poisoning might also appear mild but result in kidney damage that becomes more serious later on. iirc.
Plenty of folk out there with dogs that have eaten large amounts and seem fine. So no idea what proportion of dogs would actually suffer a fatal dose.
We took ours to hospital for induced vomiting. He’d also vomited quite a lot at home as well so seemingly most of what went on came back out the same route.