This tend to happen when your policy is to stop supporting tested, established protocols for chat clients and introducing your own in beta version to the entire planet at once.
Your search for perfect, flawless permanent security will be long, lonely and ultimately fruitless.
Already you've cut yourself off from flying, riding on trains and driving. Nobody can guarantee that deadly accidents will never happen, and indeed they do happen.
Presumably you only eat food your grow yourself. There are regular instances of contamination in the industrial food sector. Not that any guarantees can really be made, but at least contamination will be mostly your own fault.
I generally agree with this reasoning but this is not "flying", this is "flying with x airlines which dropped a plane once".
There are alternatives and one could choose a statistically safer one. There is obviously no guarantee. However, gtalk now has the highest likelihood of sending your messages to random people. That's a reason to avoid it.
What about the best chat services? In something like 18 years of chatting on the internet from IRC to ICQ, AIM, Skype, even Facebook messages, I have never seen a message go out to an incorrect recipient that wasn't the fault of my own negligence.
Well, they're also good[1]? British Airways didn't become a better airline when the Air France plane crashed, just like Air France didn't become a worse one.
1: Except, of course, IRC which is a protocol, not a service, and it was never designed to be private, but that's pedantry.
I think the overall point here is that the ability for a message addressed to one person to end up on someone else's screen carries some rather unfortunate implications for the internals of the service. Compare with IRC private messages, email, heck even XMPP.
I know XMPP does because I use that particular function at work daily, and IRC supports person to person PMs.
What I meant though is that the fact that whatever kind of shenanigans they're doing internally has a failure condition that can misroute messages is a bit scary.
Be careful! I guess the best course of action is not to use gmail chat until google announces they have fixed the issue.