Post interview communication

I wouldn't really consider what you are describing to be a "solicitation". From what I understand it is not uncommon to tell a program that you really want to go there. The problem arises is when you tell multiple places that you are ranking them number 1 and if you don't match there they will know that you lied if they ranked you high enough that you would were guaranteed to match.
This basically puts you on a blacklist if you try to get a job there in the future which is why its not a good idea.

I don't really get why telling a program that you will rank them #1 will influence your ranking on their list; although its obvious that this happens. Would you rank a place that you were less impressed by higher if you knew they were going to rank you #1? I would think they would rank solely on credentials and compatibility but I guess programs look bad if they have to go far down on their list (??)

I plan to tell the programs I like that I will be ranking them high on my list, but I will only tell one program that I'm ranking them #1. Seems like that is the safest and fairest thing to do.