routing: frame ecrow as an "ideal functionality"

routing.asciidoc

@@ -69,7 +69,10 @@ Alice now promises Bob 12 golden coins.
 She promises 12 to Bob if he shows proof that he has forwarded 11.
 The difference of 1 golden coin is the fee that Bob will earn for helping out with this particular payment process.
 
-As there is still the issue of trust and that even law inforcement does not protect Alice and Bob from malicious behavior they decide to add an escrow service.
+As there is still the issue of trust and that even law enforcement does not protect Alice and Bob from malicious behavior they decide to add an escrow service.
+To resolve this issue, all parties opt to add in a 3rd party escrow service.
+This escrow service serves as our "ideal functionality", which will later be replaced by a more trust-minimized mechanism.
+
 Of course Alice and Bob both have to trust this escrow service.
 Having such an escrow Alice could already provide the 12 golden coins to that service which would only release them to Bob if Bob shows the proof of delivering 11 golden coins to Wei.