You talk about children as if they were property.

I don't think that kids watching explicit content is something they should be doing, but treating them like property rather than someone you can genuinely influence the views of in a positive way is incredibly destructive.

Why not install an ad-blocker on the tablet and be done with it? If she's 2.5 and for some reason going to explicit sites with intention, you should be fast-tracking her to private schooling, not installing filters on information.