These threads always bring out one or two who are ridiculously over protective ... Most people on this thread seem pretty balanced though. Sometimes you get people claiming that they wouldn't leave NT 17 year olds, although they might of course be trolls...
I must say the being on pins leaving a 15 year old and phoning hourly also seems a bit hysterical. I used to babysit for four kids between 1 and 7 when I was 15, including putting them to bed... Usually for a good 8 hours - the parents would go for an early meal then theatre then after theatre late bar... Nobody checked up on me.
My 12 year old is home alone for 4 hours on days I have college, and 2.5 hours on work days. She WhatsApps to say she's home, but no contact beyond that is compulsory. If she's "off colour" (sore throat or something, not fever or vomiting) she stays home alone if ill, which is usually about 7 hours. She usually does message, often with DH who has a more flexible job and can "chat", but not to "check in".
I leave my 10 year old for up to 2 hours and 7 year old for up to half an hour. They are very well versed in what to do in emergency scenarios, who to go to if they if they need help, and in using the landline to call me, DH, two neighbors or their grandad (who is an hour away but nearly always home and would advise or find other ways of contacting help as appropriate). They also know how to call the emergency services. Before someone gets hysterical about social services this is considered absolutely appropriate and responsible where we live - responsibility and independence built up gradually, starting just before age 6. All kids get themselves to school on foot or by bus from 6 without parents.
Not leaving an 11 year old for more than 5 minutes doesn't sound responsible to me, kids need to learn gradually.
Unless you live in a really dangerous area with very high crime especially break ins obviously.