Um...
I think he was referrin' to 'shares' as a shared harddrive or printer. Some companies and individuals share devices on their computers with other systems on their network. However, if not properly protected... outsiders can gain access to these 'shared' devices from the interent. He was referrin' to somebody whom had a printer that was 'shared', but not secured with a password entry or firewall. So, you would be printing something on THEIR printer from your computer if you gained access to it. He's wanting to know if it's illegal to gain access to THEIR printer from HIS computer and print a warning stating that their printer is accessible to people all over the internet.