Plastic safety doorknob covers...no problem

Apparently those little safety covers for you doorknobs...you know the kind designed to keep your kids out of whatever room or closet you don't want them to get into...not so helpful when you have a very determined five year old.
Let me fill you in.
Yesterday, Meredith and I had a mother-daughter outing. We went to eat at Applebee's. We ate our meals then shared a molten lava cake dessert (which honestly, she could have eated all by herself). We then went to Walmart, where among more essential items we bought some craft paint (yes thank goodness I bought washable), some paint brushes, and some paper to paint on. We bought these things because Meredith has been begging to do a craft project all summer. I figured since she has an easel...we'll paint.
So we get home. She shows Jeff all the neat stuff she got. We both tell her that the painting can only be done in the kitchen or outside. Apparently that went in one ear and out the other because we discovered her in the midst of her 2nd painting in the middle of the living room floor!!!! I try real hard not to get upset and to instead think of it as "she is really wanting to paint NOW!" So Jeff and I set up the easel and paints in the kitchen. We put her in one of Jeff's old shirts, put her hair up, and let her get started. I reminded her that when painting time was over that we weren't going to get them out until the next day.
So painting time is over, Jeff cleans up the mess (big Thank YOU!), and he packs them away in the bathroom which now has one of those plastic doorknob things because....well....my child likes to play in there and I don't just mean in the sink either!
A little while later, I'm in the midst of feeding Caitee a bottle when I hear Jeff getting mighty upset with Meredith in the kitchen. She had gotten the paints out of the bathroom....the very one that has the plastic thing on the door! At first he thought someone (ME) left the bathroom open, NOPE.....she busted her way through that piece of plastic....tore it right off!
Not sure what to do now....I am taking suggestions!