What are the ways to safeguard yourself if you get traffic from your computer network?

I experience the same issues as you said of getting traffic from your computer network if I tunnel my web traffic through a proxy. I'm not sure why this is; but I'm guessing that these proxies you're using are publicly available, as most of mine are. If this is the case, then odds are there are hundreds of users making near simultaneous requests through the same proxy server as you. I'm hesitant to say that this alone would be the reason, since larger offices/businesses could probably match this traffic. Even if this isn't the case, you'll still be slapped on the wrist for another user's malicious actions, a few of which Google made mention of. If you're at all familiar with proxy servers, then you'll know that the only IP address Google knows about is that of the proxy server. Each client's IP address is known by the proxy server, but not by Google. In this fashion, the traffic sent from Google is forwarded from the proxy server to the client, and a meager means of anonymity can be achieved. For this reason, Google can only reprimand the proxy server, not the individual clients. As well, I see some other users have mentioned that the traffic might be originating from your computer. This is highly unlikely. This is evidenced by the fact that you don't run into these warnings when you aren't accessing Google through a proxy.