Are you permitted to forward the reviews from a rejected manuscript when submitting to a new journal? Suppose I have a paper rejected from a top tier journal. The anonymous reviews highlight a number of strengths of my paper, but ultimately judge that the paper does not merit publication in that lofty journal. When I resubmit to a lower-tier journal from a different publisher - presumably after addressing some or all of the reviewer's substantive concerns - can I include the entire original reviews as part of my submission? How about including excerpts from these reviews in a cover letter? 

On one hand these reviews might be seen as the property of the journal that rejected my manuscript and as part of a closed correspondence. On the other, in my role as an editor I do think everyone would be better off if we were more open about where we'd submitted and what feedback we'd received. That is useful information for an editor trying to assess the merits of a paper and decide whether to desk reject or to proceed with a full review. 

I'm interested both in formal policies (I don't see any for the journals I frequent) and in general thoughts about the ethics of doing so. 

Addition: To clarify, I am more interested in whether it is allowable to forward these reviews than I am in whether it is advisable to do so. The latter question depends so much on the particular circumstances that I cannot imagine a single universal answer - though it is interesting to read the thoughts of the community on this issue as well.
I have done this a couple of times (but not always going down in the journal hierarchy). In my cover letter I indicated that "the paper was previously submitted to [blah], but was rejected because [...]. A copy of the report can be obtained by writing to [editor name]."

The motivation for not including the copy of the report is that it keeps me honest. I can't just select the bits I like.

I have never had any problems with this approach, and I believe it to be the right thing to do. It saves editors' and referees' work.