In addition to what the others said, which I agree with, telling someone you are ranking them highly is a pretty transparent way of saying you're not my number one, but I want you to rank me highly, in case I don't get what I want. There's nothing wrong with it, but I think the only email that has value is the one that states to your top choice that they are your top choice. Anything less is meaningless. And as I'm sure you know, if you tell them it's your top choice, it better be your top choice.
I didn't actually use the phrase "rank highly" in any of my letters. For my first choice, I explicitly told them they were at the top of my list. For my other spots, I would tell the programs that I ranked them in my "top four", for example.
Here's another question. I told Program A that I would rank them number one after I interviewed (and I really meant it), but after 2 emails and 1 voice message to the PD, I did not receive anything by way of a response. A month later, I interviewed at Program B and decided I liked it better than Program A, especially since Program A basically ignored all my communications. So following my interview, I told Program B that I would rank them number one (and I fully intend to).
My question is, first of all, did I violate any match rules? I know it's unethical to tell multiple programs you would rank them number one. But in my case, I actually meant what I said in the letters and it wasn't my intention to tell two different programs that I would rank them number one. If Program A had been responsive and actually given me some indication that they were still interested in me after the interview, I never would have even considered telling Program B.
Second question is, Having told Program B that they're my number one, do I need to tell Program A that I no longer intend to rank them number one? Even if I sent them an email to tell them this, I wouldn't be surprised if I didn't hear anything back, since these people either aren't interested in me as an applicant, or they aren't interested in answering their emails.
Any thoughts? Have I violated a Match rule? Should I have even shared this information in a public forum? Will SDN protect my privacy should this issue come under investigation? Why am I still typing?