I agree that scouts should be cancelled and you get refunded half of what you put into it.
If they finally give this much-needed feature and if we do cancel a scout within seconds or even a few minutes after an accidental click, a full refund is only fair because they haven't even set foot outside my city yet unless they're like the Flash which I highly doubt.
With all the bugs this game has, players are bound to make mistakes or the game does something without the player doing anything. Just earlier, I clicked on the World Map or Research icons to check something and then went back to my city. I was careful to put my mouse to the right edge of the screen where there are no buildings before pressing C because I knew it was near the time for me to collect goods and I didn't want to accidentally click on anything. I was surprised to see coins vanishing from a residence as if I'd collected them. I checked my pointer and it was there on the empty right side of my city. First time that has happened to me but I won't be surprised if other things happen due to this very buggy update.
However, if you stay within your scouted map, you will never "accidentally" activate a scout.
I regularly go to the edges of my scouted map to check on the unscouted province types and costs so I can list them down and arrange them in order of priority. Even when I have that list, I check the edges again when I start conquering to be sure I got things right. And, yes, I have accidentally activated a scout or two, sometimes not within an intended province because of system lags. And how on earth does one scout or survey an area if you stay within your scouted map?
At least that's how I've done it.
That's how I've done it too. It's also how I first accidentally spent diamonds. There should be in-game info about the diamond box in settings for noobs. It took some time before I found it.