Photoshop on 2 computers

When purchasing a license for Photoshop I know you are able to use it on 2 computers, but not at the same time. I called Adobe customer service about another matter, and happened to inquire about using Photoshop on 2 computers and was told that if I were to use it on 2 computers at the same time it would "crash my system". I only have 1 computer so I have no way of checking this out. It sounds to me like rubbish, but I wondered if anyone could confirm that it's not true.

Thanks in advance.

Doc