I agree: starting off my current allotment, I bagged up all the nasty weeds with persistent roots such as creeping buttercup, couch grass, bindweed, dandelion, docks, nettles (What a depressing list) and three years later put them back into the soil with a great deal of vengeful satisfaction as a nice brown mixture which certainly did not spring back to life.
That allotment is reasonably clean now - just needs regular hoeing for weed seedlings and a close watch around the edges where the communal grass paths creep into the plot.