I don't understand why this is such a contentious topic. You shouldn't have to check your email after work. However, I don't think it's unreasonable to contact

I don't understand why this is such a contentious topic. You shouldn't have to check your email after work. However, I don't think it's unreasonable to contact an employee if there's an emergency or something very urgent, as long as it's an infrequent one-off exception. Surely we can evaluate these on a case-by-case basis? It probably depends on the company size, its field, and the potential impact.