honored guest or honored host (II)

My wife posted the following:

My husband is (not always) patiently learning with my son in preparation for the latter’s bar mitzvah. When he mentioned what he was learning, I thought I will work it into a discussion of invitations from a Torah perspective. Anyone have some insight into the following?
Megillah 28a. R’ Eliezer declared that he refused gifts and invitations. He would say to those who would invite him, “Do you resent my living? For it says [Mishlei 15:27] ‘Soneh matanos yichyeh’” [One who despises gifts will live.] Rav Zeyra [in contrast] would also decline presents but would accept invitations. He explained, “it is not for my honor but for that of the host that I accept the invitation.”

If you have any ideas, please visit her site to comment. Since she has put me on the spot, here are some initial thoughts to provide some grist for the pilpul mill:

R’ Zeira’s insight brings to mind the sugya in kiddushin of adam chashuv – the gemara (kiddushin 7a) tells us that although normally a man must give something of value to a woman to effect kiddushin, in the case of a very important individual the woman can become mekudeshet by giving a gift to her groom - the act of such an important person accepting one's gift itself bestows hana’ah, benefit, on the giver, which serves to effect the marriage. It is hard to accept that Rabbi Eliezer disagrees with this principle, so how can we distinguish between cases?

Another gemara (Brachos 9b) inform us that one who is someich geula l'tefilla will not come to harm that day. R’ Zeira (note, same R’ Zeira as above!) disagreed, claiming he was someich geulah l’tefillah and was harmed! - he had been ordered to bring a hadas to the palace of the king. The gemara retorts that such an event is not a bad occurrence at all, as anyone would be willing to even pay admission to gain entrance to see a king! R’ Zeira recognized (based on the gemara in Meg.) that accepting an invitation is often more of a benefit to the host than the invitee, so why here did he not recognize that receiving the benefit of an audience before the king outweighed the small gift he had to present?