The spankings for both Marek and Jan were very well deserved and necessary.
Much like Mary, spanking has been my primary form of punishment when the children have misbehaved. I have used other punishments as well, but they have been used in conjunction with a spanking than instead of. So yes, spanking has not only been the best punishment in my home for not doing chores, but the only one.
My girls had their share of instances where I needed to spank them for not doing their chores, but it was more in not doing a good enough job on them than just outright ignoring them. With my son, he did his share of both! My son hated chores, and where he did them more often than he didn't, he also often complained about it and I especially had trouble with him cleaning his room. He received plenty of spankings for that alone over the years.
I agree with you that is most certainly a form of disrespect as well as disobedience when you know they have deliberately not completed them.
Of course there were times I heard from my son, "I'm sorry Mom(my), I forgot." But I know it was usually because he really didn't want to do it. However, whether he really forgot or just said so, he earned himself a spanking either way. Forgetting has never been a reasonable excuse not to get chores done. Andy isn't as stubborn as my son was, but he has had his share of instances where he hasn't done his chores and has received spankings for it.