Let me be the first to say
... LibreOffice! (or OpenOffice, which would have been the current version at the time of the cock-up)
A label company near Chester has handed over £24,800 after it was caught by the Business Software Alliance using unlicensed copies of Microsoft Office. The BSA was contacted by a whistleblower who asked them to investigate the company. Disgruntled ex-employees are a common source of BSA tip-offs. System Labelling Limited was …
If an organisation has reasonable suspicion that you have counterfeit goods on the premises (e.g., a whistleblower) then they can talk to Trading Standards.
And Trading Standards do have right of entry
Personally I'd take the Ernie Ball route: http://news.cnet.com/2008-1082_3-5065859.html
"Michala Wardell, Chair, BSA UK Committee, said the case showed that using unlicensed software was a false economy".
It's not clear that the case demonstrates this. Most who people who use "unlicensed" software get away with it, so the question of whether or not it's "economical" to do so rests on the advantage of not paying against the possible cost of getting caught.
Wardell's statement is little more than an advertisement for her organisation.