i don't think its a matter of being lazy to not read the passages (esp. on PS).  Most of the passage gives you extraneous information which is not needed to answer the questions. so basically it just eats up your time which could better be spent on questions.  I feel like it works better for me on PS to go back to the passage to look up specific information that the questions asks, verses reading it all in the beggining and then (usually having to go back to the passage anyway because I didn't get it the 1st time around).  I do skim to look at any numbers, equations, graphs, tables, and just look at their titles or what they're for for PS.
In BS, i think you guys are right. It is alot like a verbal passage sometimes, where the answer is based on semantics, verses a crucial understanding of the science or system, so it helps to have read the passage.  Some passages that are not experiment based, and that talk about systems have many questions that are answerable without reading the passage tho.  Like if the passage is talking about how a particular system works (kidneys, blood circulation, or respiration) I will just jump straight towards the end of the passage, where it will give some clarifying information...like what goes wrong if this part of the system doesn't work properly (or something like that), and there will usually be a question about that.  Usually they give some kind of clarifying or critical information towards the end, i've found (but then again i could totally be imagining this in my head- i dont know lol) So i just thought it would be interesting to see what everybody else thought too. Thanks and please....keep your thoughts/opnions coming...