Yes, it can. This has been brought up a couple of times. I've recently seen a report of an issue that allows for custom local maps to be used to create an exploit on server.
For PvE it's not a huge deal, with the exception of the exploit. For PvP servers, it is potentially game breaking in all cases.
When you connect to a server, the map data is stored locally in your saves folder.
D:\Games\7 Days To Die Saves\a17\SavesLocal\0AA3F4E0C79DF74CB16E3E4329B6EB9C\World\prefabs.xml
This includes the world preview image, and splat map, so you can get a pretty good idea of what the entire map looks like before you get set to exploring it.