Remove the last three-state references from the spec

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/placement-switch-spec.md

@@ -46,7 +46,7 @@ Worth stating plainly, because this is where people assume more than is true:
 
 ---
 
-## The proposal: three states, chosen by the member
+## Two settings, chosen by the member
 
 On the dashboard, under "Share this position":
 
@@ -76,11 +76,11 @@ Consequences of that choice, all intentional:
 - If Terry is on **Direct**, everyone he personally brings in starts on **Direct**.
 - If one of them switches to **Team first**, only that person changes. Their own future
   referrals then start on **Team first**, because they are now the sponsor.
-- If Terry later switches, only members on **Follow my sponsor** move with him. Anyone who made
-  an explicit choice keeps it.
+- If Terry later switches, **nobody already in his team moves**. Only people who join after the
+  change start on the new setting.
 
-That last rule is what stops the tree becoming unreadable. An explicit choice is never
-overwritten by someone above.
+That is what stops the tree becoming unreadable: a setting is copied once, at join, and an
+explicit choice is never overwritten by someone above.
 
 ---
 
@@ -121,8 +121,9 @@ Ambiguous under spillover. *Handling:* the sponsor, always. Written into the spe
 is the same every time anyone asks.
 
 **3. Settings drifting out of sync.**
-If a leader changes their mind, what happens below? *Handling:* only **Follow my sponsor**
-tracks changes. An explicit choice stays put.
+If a leader changes their mind, what happens below? *Handling:* nothing — the copy happens once,
+at join. Nobody already in the team moves, and the panel shows which sponsor a setting came from
+so the history is visible rather than mysterious.
 
 **4. Spillover expectations.**
 Members who are used to receiving spillover from an active upline will see it slow down if that