Yes, the "Page refresh" message can happen if your browser reloads the page, for example, if you click another action when the page has not finished loading on your end.

The system is set up to either record your guess successfully, and the outcome, or leave the same amount of coins. So if you get disconnected before the data travels both ways gameplay is not affected. If you make a choice and the server doesn't receive it, then nothing happens either way. If you make a choice and the server receives it, but you don't receive the answer your coins are still credited or debited as the case may be.

If you tell me the amount you played and address, for example, I can tell you if a choice was received and what it was.

EDIT: I'll probably have to change that to just display the last game outcome so it's not confusing.