Search example for free-text and thesaurus/MeSH search skills training

I have just had an enquiry which really demonstrates the importance of searching free-text and thesaurus/MeSH for a comprehensive search. The question was "find evidence of the effect of mobile phones in a clinical environment." You need to search for mobile phone as free text and cellular phone as thesaurus/MeSH term or you will miss out on many useful results. Then, for clinical environment, I went for healthcare facilities, but as a related term searched for electromagnetic fields and equipment failure. I thought the mobile phone and cellular phone aspect of the question would be useful as an example in a search skills training session.