This is just a way to say that whatever is forbidden is most desired.
You’re parents warned you to stay away from strangers, even/especially if they offered you candy; but they just did not want you to know that the candy they were giving you was crap!
Just kidding. Kids, STAY AWAY from strangers.
This is just a funny shirt and we in no way encourage you to go with strangers.
Stranger are weird and can be dangerous.
See for yourself.