As far as I know, the receiver cant get tricked assuming:
- The receiver has had his bitcoin address ready(probably pre-copied address to his notes app, or a screenshotted QR code)
- The receiver is viewing his bitcoin address through a reputable and untampered app(Mycelium, Electrum, etc)
Not sure how a 'fake blockchain' can affect the receiver's mobile app, unless the sender asks the receiver to download a wallet of this 'fake blockchain'. And take note that the receiver can verify through block explorers if he actually received the funds in the first place.
In the top of my head, the only way the sender could tricked the receiver is probably through a double spend, or through a phishing site redirection through the wifi's DNS settings if the receiver is going to use a web wallet through a browser(and not a wallet app).
Correct me if I'm wrong of course.
I was thinking about the receiver that is using bitcoin-qt wallet.
So if he connects to the forked BTC blockchain he'll download wrong blocks then the sender will send him BTC, a valid transaction on the forked blockchain, and then the receiver will go home, connect to the right blockchain and see the transaction has never occurred.
This is of course not possible with Electrum, but is it possible with bitcoin-qt wallet, assuming the receiver doesn't check on any other source his transaction when he is still at his host's home?