To all you folks saying, "Well I was a latchkey kid....."
Okay, so was I at around age 11 or 12 (maybe even sometimes before that - I don't remember) but these kids were 4 & 9.
Florida law does not have a preset age for leaving a child alone but they do require the situation to be "appropriate for the child's age or mental or physical condition". Very few 4 year olds can adequately care for themselves. Some mature 9 year olds could do a pretty good job of caring for a 4 year old for a reasonable period of time if she didn't need emergency medical care.
HOWEVER - the very fact the mother apparently felt she had to padlock them in the house from the outside suggests she does not feel the 9 year old is mature enough to stay safe on his own. I was NEVER locked in my house / room / etc and I'm guessing you other latch key kids were not either.
Secondly, these could have been 17 year old kids and it would still be wrong / illegal to padlock them inside of the home. If there was a fire that could get really ugly really fast.
FL Dept of Children & Families - Frequently Asked Questions
30. How old does a child have to be to be left home alone?
Chapter 39 of the Florida Statutes (F.S.) mandates that the Hotline be contacted when any person who knows, or has reasonable cause to suspect, that a child of any age is being left home alone without adult supervision or arrangements appropriate for the child's age or mental or physical condition, so that the child is unable to care for the child's own needs or another's basic needs or is unable to exercise good judgment in responding to any kind of physical or emotional crisis.
The Hotline Counselor will assess the information provided in the call and make a determination of report acceptance or non-acceptance based on statutory criteria.