Because the plastic in the cup acts as an insulator, the charge that exists over the rest of the cup's surface remains in place. Ionized-air blowers are available for service benches. The blowers can be a nice insurance policy, in case nonconductive materials come into contact with sensitive electronic components. Even if you take this precaution, however, it's still good practice to have a policy of keeping plastic cups and other materials away from the service bench. You'll also want to give some attention to the type of floor covering that's being used in your offices.
Many synthetic carpets are complete insulators and promote static build-up.
If you're outfitting a new office or putting new carpet into an existing one, look for carpets that are conductive - either by nature of the material they're made of, or from some coating that's been applied. You can also treat existing carpeting with anti-static sprays. The only problem with this is that most of these mats are electrical insulators, which again means there's potential for static charges to build up. An alternative is to buy special static-dissipative chair mats. These are made of conductive plastic and come with a ground wire that you can connect in the same fashion as the keyboard anti-static strip mentioned previously.