If someone takes the ip address method to the next level it really should be changed to provide some kind of security, like agree on a password/address or something ahead of time.  Sending to an address and creating the key automatically provides no authentication and there's no recourse if it went to the wrong place; the intended receiver is unaware you even tried to send anything.  It is trivial to proxy it and MITM that kind of activity and with the value of bitcoins rising it might just be worth doing eventually.

I consider the ip address sending a local testing feature more than a production level feature in the way it is currently implemented.  One possibility that could work is if the receiver provided a public key (address) to you first and you used a combination of internet address and public key.  It is not as convenient but the alternative is to just send it to the ether and hope nobody grabs it before it gets to your target.  If anyone has used liberty reserve or something similar you know it is certainly not convenient to log into and such, but when it comes down to a choice of losing your money or dealing with an inconvenience I think most people would prefer the latter.