"Networking-proof" banks?

This may be a bit of small-sample-size, ignorant-college-student overgeneralization, but in my experience reaching out to alums (top target) at various banks, I've come across a wide array of approaches that banks take toward tracking and/or being proactive about networking with regards to recruiting (my experiences are for SA).

Most of the BBs seem to have a very structured way of tracking contacts and collecting resumes, with some even having all the "networking data" managed by a member of the school team's recruiting analyst class. I've seen some boutiques do something similar, but most have been less structured, though still open to it. That means while they won't "track" candidates firmwide, analysts will be sure to ask for a resume after (or bring it up during) a phone call and meaningful referrals to HR are commonplace.

However, some boutiques seem damn near impenetrable (remember, we're talking about alum emails here, not totally cold emails). Most emails into the firm fall on deaf ears, especially at the higher levels. If an analyst does reply, the resulting call's an informal conversation without the subtle recruiting undertones that usually come with this type of call. A follow-up asking to be referred to others in the group (or, god forbid, one directly related to recruiting) likely meets radio silence.

So, I ask those of you with more experience than I or even at the other side of the table--are some banks deliberately colder to the (virtual) touch of alumni/student contact? If so, what's the reasoning behind that stance? Do groups with a more notorious culture in the office (e.g. Lazard) tend to adopt a more anti-networking/"pure numbers" recruiting effort?