What Age Should A Kid Be Allowed To Go Trick-or-Treating Alone?

My 11 year old son Jackson has started going through that phase where he wants to do things with his group of friends without Mom and Dad.

His first experience happened last week when he went to the fair with 3 other friends along with his friends parent.

Now ... he wants to go Trick-or-Treating with his group of friends without my husband and I.

Normally, we go Trick-or-Treating as a family.

I'm on the fence about letting him go Trick-or-Treating with his friends. On one hand I know that Jackson is a responsible, polite, good kid. On the other hand you never know what kind of trouble other kids could drag your kid into.

At what age do you let your kid go Trick-or-Treating alone?