There's an interesting clause in here http://www.adobe.com/products/eulas/pdfs/Citrix_Policy_AX_AXI_11-12-20 12.pdf
This concerns using Acrobat on a terminal server, which by its very nature lets multiple users run the same software at the same time.
Interesting points include
The total number of users (not the concurrent number of users) able to use the Software on
such Computer file server(s) may not exceed the Permitted Number
does not permit you to install or access (either directly or through commands, data or instructions) the Software ... for operations not initiated by an individual user (e.g., automated server
processing)
The clause about total number of users seems to relate to a count of licensed humans (what is a "user" if it is not a human?) and does not permit licensing by role or by computer. Or so I might opine if I were (and I'm not) a lawyer.