It's not a wrong address but I did sent it to other network for this example to ERC20 tokens but I sent it to my main ETH wallet on this exchange. But thankfully the exchange was pretty kind to helped me out and they sent back the token to correct place in that exchange, but after that I learned my mistake and double or even triple check everything.
- Would you be more comfortable using a helper?
Not at all, if that means using third party application just to make sure you are sending to correct address then that's not a way to reduce the risk.
- What do you use today to mitigate this risk?
Just double check everything, as simple as that.
Copy pasting for several times, do some Ctrl+F if you are on browser, I have tried that until today and I have not received any issue at all after that incident that I have told before above.