Basically, the “deeming” rule was put into place I think right back at the beginning of the standing committee structure in 1968, but I'm not 100% sure about that. If you don't have some way of ensuring that the estimates get back out of the committees to the floor of the House, then you open the door to all sorts of tactical games within the committees to avoid having votes on them and to delaying and possibly kind of gumming up the larger parliamentary consideration of the estimates. Those activities wouldn't necessarily have to do with the substance of the estimates; they could have to do with almost anything.
So the deeming rule is basically a way of ensuring that the whole process isn't brought to a halt by what would amount to filibustering. I think that's valid. If Parliament decides to bring the estimates process to a stop, either in some small way or more broadly, that's its right to do, but it should be done on the substance of the estimates and not as a result of some kind of clever tactics in a committee.
The second point—and it goes back to this basic mantra about incentives—is that if committees are not motivated to look seriously at the estimates, then deeming or not deeming really doesn't make much of a difference. So you just do what allows the system to keep working, I think.