At best it is a well-intentioned person who thinks they can do it,but can't. At worst, it is a scam or just a plain dirty trick.
With the information requested, one could simply cancel the tickets. While that won't do the bad guy any good, there are all kinds of bad people out there.
For all the people here who think that they can invent some way for someone to do this, they really can't and they have no reason to do so.
In this day and age, anyone who supplies information such as is requested over the internet to an anonymous person is part of the cyber security problem, not solution.
Do Not Do This.