Lying to my kids

So, I'm a very honest person, except when it comes to my kids. I tell them stuff like the neato will eat their toys if they get left on the floor or if they go outside and don't tell me, the bad man will get them. Stuff like that. My latest lie that I told to Maddy was that the guy who counts people during Sacrament meeting is checking to see if people are being reverent. I just don't know, the last 2 Sundays, she has been so well behaved, I don't want to tell her the truth. ha. However, I guess one day they'll figure me out and will just think I'm a big liar :( Do you think those kinds of lies are bad?