Perhaps the real costs are what motivated the factory owner(s) to secure the network in the first place... Lost time and legal liabilities!

How long before more hourly workers start using the network? Start playing network games? Start streaming network media? Start posting in social networks from the factory IP? Pron? Etc.

Unfortunately in the US some hourly wage employers feel the need to make the employees paid time as tedious as possible.

In these situations some hourly employees tend to find anything to help relieve that tedium. Some are quite ingenious too!
Sometimes these employee schemes end up costing the employer more than what the security was designed to "save" in the first place.

If breaks are scheduled for everyone at the same times, the smart play for the employer may be to provide free access only during those times.

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As more and more of our personal lives are managed and conducted on-line, I have a feeling that timed internet access may be used in the future as a means of crowd control or to prompt simple conditioned responses.