You know that episode of the Simpsons...

[minimatron]

I have this problem too. DD1 self weaned from her dummy at 10 months. When dd2 came along (dd1 was 19 months) we got the dummy out and dd1 decided it was hers. So after about a week of her stealing the dum, I just got rid of it for dd2 as well. If dd1 sees other kids dummies, she pretty keen to nick them and have a go! Shes now 3 and still is facinated. She even tries to use the dolls dummy or pretends the bath plug is one!!! So am guessing that dd3 when she comes along will not even know what a dummy is!!!

[Catastrophic]

My DD3 does this... She will steal DD2 dummy and put her self to bed! I'm hoping it's a phase and she'll grow out of it...