This never worked for me. Its very common to hear people advise this, but I dont think it works, I see it as avoiding a problem rather than getting it out of your game.
If you found a leak where your opening too much junk from EP, the answer isn't to start opening nothing from EP, but to fix your game and start folding the junk, this is the same imo, this stops you seeing the results in the short term and avoids the tilt, but it doesnt solve the long term issue/s that you may have which is causing you to react badly to losing/breaking even.
So, your problem then is that your too results orientated, you need to figure out why your getting frustrated at breaking even or why you can't handle it if your graph is steadily rising, write down what goes through your mind when you click the cashier and see that your down, are you pissed because you think your better than everyone, are you pissed because you think you run worse than anyone else (my personal issue!), are you pissed because you think you deserve to be winning b/c you put a lot into improving (and you do btw as your always posting in HA).
The answer to your problem will be different depending on the reasons that your reacting badly, and long term I dont think it will improve by self-banning checking the cashier....i've tried it!