There is no problem using your pc at the office nor in an internet shop as long as you are using the same account. But, here comes the complication:
- If you have same internet connection and one of your officemates signed up under the same upline or referrer, both of your accounts (you and your officemate's) might be construed as ficititious or as a means to cheat. When this happens, all three accounts (yes, including the upline) can be suspended or deleted.
The above scenario is applicable too in the internet shops. An internet shop uses only one IP address so it is really unfortunate when an upline and his referral (or two referrals from the same referrer) accessed a PTC site in one particular shop.
Some PTC sites allow more than two accounts per household. But, many are using the issue of same IP address and fictitious accounts to avoid paying.
So for me, it is best to keep your PTC in one computer and in one internet connection. Do not ask others from your office or from your home to join under you in any PTC site. If you are at the office, make sure that you are the only one doing the clicking. You do not have control in an internet shop so don't do PTC thing out there - avoid the risk and besides you might end up paying more at the shops than the earnings you generated from clicking.