as they have already explained, once it's up to date, it doesn't need to connect unless you wish to go online for MP.
for me your not seeing this as how it works,
i'll explain if you let me,
add the game to your firewall and then see if it ever happens again, In product requirements it says internet required for MP and nothing about being required for SP as none is, but as it has a kind of inbuilt internal server, blocking it with a firewall stops the game from initializing and working as designed,
so step one, update game to latest version and allow game in the firewall / Anti Virus white or safe list and play from a admin account and run the game exe as admin, and it won't happen again, even when your travelling and don't have net access.
http://www.matrixgames.com/forums/tm.asp?m=3483925
Security Applications
Antivirus and firewall software play an important role in your computer security. They help protect your computer from viruses, malware and spyware infections. However, when protecting your computer, they can prevent legitimate programs, like Pandora, from installing, updating or running. Adding exceptions for Pandora executables or disabling your security software can help resolve these conflicts.