I found the following text when looking up KDFs:
In comparison, the so-called DHAES mode in IEEE 1363a mandates to use the binary representation of the sender’s public key as an input parameter.
where a quick lookup suggests that DHES and DHAES are simply earlier names for ECIES.
What would be the reason to include the sender's public key into the KDF as a parameter? Other ECDH based schemes do not seem to do this.
If the sender's public key is altered then the calculated shared secret $Z$ would be invalid and the KDF would fail to generate the correct key anyway. Is this just an additional spurious security measure or am I missing some significant reasoning?