Visual800 - that is because you were reselling an OEM version. That is different than a Student Edition and Retail Edition. OEM versions of software are ONLY allowed to be sold with a specific peice of hardware - this is in the licensing terms. For example- OEM Microsoft
Windows can only legally be sold with a peice of
computer hardware. In that scenario they are not as specific and it can be something as simple as a new mouse. On Photoshop I'd guess an OEM version might come bundled with a tablet or even a
computer. OEM versions CAN be legally sold BUT it MUST be sold with the hardware it is intended to be sold with.
In other words - say you buy and off the shelf
Dell computer with
Windows 7 on it. You have an OEM version of
Windows 7. The only legal way to sell that copy of
Windows 7 is if you sell the
computer that it came with along with it.
If you somehow get software bundled with something (or not but it was intended to be since it is an OEM version) then you need to be aware that it probably can only later be sold with whatever it originally came bundled with. Student editions have their own set of rules. Many can never be resold legally while some can. License, resale, transfer restrictions vary from company to company and from program to program. The end user not being aware of the licensing terms is not the software makers problem.
On Adobe CSx products it has always been 2 activations allowed. As already mentioned this is NOT intended to be for 2 seats to use at the same time. Adobes intention of alowing 2 activations is so you can install it on your desktop and your laptop but both copies are never "legally" allowed to be used at the same time. Most do so anyways and I'm certain Adobe is well aware of this. One nice fact on Adobe Student editions - they can be upgraded to the latest version at the regular retail upgrade price. Once upgraded a Student Edition legally becomes a full Retail edition. At that point it can legally be used for commercial business and resold/transferred to a new owner.
These are of course specific examples. Other programs and companies will all have their own set of terms and rules. Some never allow a program to be resold, ever. Some make you jump through 50 hoops. I look at like this - if I'm spending under a couple hundred buck I really do not care if I can resell it or not. Might check if I can return it if not satisfied or something if it's some new program I want to try that has no demo version. Over a couple hundred bucks I will find the licensing terms and read them first so I can make a better decision.