Mrinalini is never exposed!

Guys, I always wonder how Mrin is always saved inspite of causing harm after harm to both RaDev, what ever scheming she is doing she is doing by staying home almost in front of every one, but never gets caught, just gets yelled at or hears some sarcastic remarks from Dadima or Dev but so far no one has traced Mrin to her devilish games. Radh has a clue how Mrin can manipulate, Dev knows it too but never pursues enough to trace it back to Mrin and confronts her, Vivek very well knows what a trouble maker his wife is, he has warned her a few times but still is clueless about the degree of viciousness she carries towards Dev & Radh. Mrin is always hanging around Chachu & Arjun, but how come no one questions her? Even Birju knows but he got burnt confronting her. All the evil in PB is initiated by Mrin and even after more than a year into CB no one has put Mrin in her place. Vivek has warned her but just a lame warning is useless, Mrin is a big league player, some sarcasm is not going to stop her from doing mischiefs.