How to research client infrastructure

Today, the deadline for answers to my questionnaire is ending.
I sent out a short form to collect information on monitors, screen resolutions, graphic and sound support, installed browsers and versions, plugins, settings (javascript, active x) etc.

I thought it was clear, but there always seems to be space for misunderstanding: how come that it coordinators tell me in answer #4 that flash plugins are installed, in answer #7 that no file formats are blocked and in answer #9 that employees can not play swf or flv files?

Everytime again it is surprising, but even in the very networked times we have now the only reliable way to find out what is really going is to go there, turn on the computer and have a look on your own.
That eats a lot of time, but it saves a lot of worrying.