Backblaze on a LAN can backup the whole company?

Unlimited backup storage you say? So if I put one Windows PC client connected to backblaze, all other machines can use some software to use that machine over LAN and use it as a backup server. What's to prevent that?

The single PC can cache the backup data, only download backups from backblaze when absolutely no other backup copies exist locally.

If backblaze allows this, I think this can be an interesting low cost device for backing up potentially huge amount of data cheaply.