NO. I told the dive guide before jumping into water that he will be my buddy.
If I do not have a buddy that I am familiar with, the dive guide is the ONLY choice.
So, what do you do if there are an equal number of divers on the boat plus the dive guide? Do you leave another diver without a buddy because you don't know him/her, and attach yourself to the dive guide, or do you force the dive guide into a threesome? Other than local diving, almost all of my dive buddies have been insta-buddies, some of which have been great, and others not so good. However, I have never turned down a dive buddy request or a pairing by the DM. The way I see it, the insta-buddy might need my help during the dive, or I might be the one needing help. Either way, I am happy to be there to help if needed, or to have potential help if I need it.