I've also seen people pass, but pass just barely, sometimes with controversy. It would be pretty humiliating to realize you're 'that guy' whose test everyone who was there remembers...
The hard part is that you are embarrassing your Sensei and school...even more so than yourself. They were the ones that put you up to test after all, and the school that sent a poor quality Aikidoka up will be judged by the quality of student they present to the technical comity.
I've heard to many stories about Yamada Sensei, or other Technical comity members "having a word" with the Sensei of failing students. I've heard of Yamada Sensei "having a word" with students who had passed, but barely passed, black belt tests as well. So my only opinion would be is, if you are going to test, be prepared. I think you are gonna want to look like a black belt on the test coming off the bat. It is embarrassing to pass, but pass while struggling.