However, unless you have signed up to two different ISP's and each editor uses a different one, you will share the same ip address. Checkuser can easily see the ip behind each account name, and if they see the same ip based accounts are editing the same or similar pages they may assume it is the same person. Further investigation may conclude there are different computers being used, but the detail of the ip address may indicate it being one private residence. In such circumstances, CheckUsers may determine that the likelihood is that there is sockpuppetry - and it should be noted that WP:Meatpuppets are considered the same as socks where multiple editing of the same pages occur. So, I suggest that you are careful in how you act as regards your siblings edits in case someone believes you are co-ordinating your edits in violation of WP policy.