It is clear that laws are drafted with an immense level of attention to minute legalistic detail with care often put into the choices of every word. Indeed, needless to say, courts and litigation parties often agonise on the choices of single words, and the questions of whether or not those choices can be seen as intentional, and even when they're found that they can't be seen as intentional, there is an apparent imperative to treat them as though they are, anyway.
From TV legislature-floor debates, it seems that generally the provisions are debated at the level of "should we include or reject this amendment proposed by X legislator?" And not, "should we change this "and" to an "or" or add an "either" in this clause of this section?"
Which is quite understandable, because, meanwhile, legislators are extremely busy people and largely politicians rather than lawyers.
So to what extent do legislators actually familiarise themselves with the finer details of laws that they debate and pass? In systems with bicameral legislatures, does this answer change significantly between the upper and lower houses?