Privacy violation depending on who passes a compile-time argument?

[rcorre via Digitalmars-d-learn]

Can someone help me understand why the first line is fine, but 
the second triggers a deprecation warning for access to a private 
variable?

---
import std.traits;
import s;

pragma(msg, hasUDA!(S.getMember_i, attr));   // fine
pragma(msg, hasUDA!(S.getMember!"i", attr)); // deprecated

/++ in module 's'
import std.traits;

struct attr { }

struct S {
   @attr private int i;
   alias getMember(string name) = Identity!(__traits(getMember, S, 
name));
   alias getMember_i = getMember!"i";
}
++/
---

getMember is not a mixin template, so it seems like 
__traits(getMember, S, "i") should be resolved within the 's' 
module in both cases. Why is passing the string "i" from another 
module a violation even when getMember_i is doing the same thing 
internally?