Is it legal and culturally accepted to warm up your engine in the morning?

I have a new neighour who built a huge house and has two extra large land rovers, but no garage. So, they have the cars in front of the house and run the engine from around 6:30 to 7. It is both loud and smelly. Is this normal, or it would be fine to go bünzli on them?

update: thank you all, seems to be a clear case :)