Agreed, but there's no delivered (but not necessarily read) receipt that applies to email so that was closest I could think of that counted. The overall point remains: sending an email, with no further evidence, does not count as proof of delivery (all the way to the inbox).
I don't know how laws work here but I can't imagine having adequate "proof of service" fully insulates you from all possible claims of non-receipt, especially electronically? Like what if the recipient was in a coma or on active duty in the middle of a war zone or something? There have got to be exceptions here to handle some cases of non-receipt despite proof of delivery, so the question of whether spam classification might be one such exception doesn't seem automatically invalid.
> Like what if the recipient was in a coma or on active duty in the middle of a war zone or something? There have got to be exceptions here to handle some cases of non-receipt despite proof of delivery
If the recipient was in a coma, this question couldn't arise at all, because they wouldn't be able to use the service.
