theoretically stupid, but bound to happen ...

[empoweoqwj]

What if I send bitcoins to a completely random hash address? By random, I mean not a real address I have selected randomly, just a random value that satisfies the requirements of a bitcoin address.

Will the bitcoins just "disappear"? Any other outcome?

As an example of real-life, I could paste a bitcoin address into a send box, but in a drunken stupor or "baby intervention", alter one character before pressing send. What would happen?

[Gabi]

If you mistype a character, then the address will be invalid and you would not be able to send the bitcoins.

But if you send the bitcoins to a valid address for wich the private key is unknown... yeah well, byebye bitcoins

[empoweoqwj]

ah great, thanks, that's a green light for the drunken stupors then 

[Gabi]

Yup, if you only mistype one character or so, the address will become invalid.

[cbrcs]

Well someone really lucky might end up with a freshly generated address that already has some coins on it. Right?!

[DeathAndTaxes]

Well someone really lucky might end up with a freshly generated address that already has some coins on it. Right?!

Possibly however if you by extremely back luck (1 in ~4 billion) mistype an address which actually ends up being a valid but unknown address the most likely scenario is nobody every (not today, not tomorrow, not in 5 billion years when our sun burns out) produces the private key which corresponds to that valid but unknown address.

Hint: the odds of someone randomly producing a private key corresponding to that address is the same as the odds of someone producing a private key which corresponds to any known/active address which for all intents and purposes is ~0.0%.

[wifihero]

Somebody asked me a similar question the other day.

According to https://en.bitcoin.it/wiki/Using_Bitcoin, the "Client will refuse to send payment to a misspecified address."

There is a checksum in place to ensure the address is valid, so you are unable to send to an invalid address.