[dspillett]

You are not going to be the only person appearing to come from that IP address – many will likely be NATed through it.

The more significant concern is if you are the other side: if you deliberately run some sort of VPN or other proxy that others can use, or less deliberately do so. Many hacked or otherwise suspicious browser add-ons, and other malware, will make HTTP(S) requests & other connections on behalf of their C&C hosts and to your ISP or anyone else those requests will be largely indistinguishable from those that are the result of your activity.