Why not just point people to these links - all found within 5 minutes. There are certainly others and I am certain that most of your requestors have already been to them. What you probably need is a large-print statement claiming that your site and its webmaster are unable to assist in researching individual veterans.
MLU has this page -http://www.mapleleafup.org/locator/research.html
Library & Archives has a section for military geneology -http://www.collectionscanada.gc.ca/lac-bac/search-recherche/anc.php?Language=eng
GeneologyLinks has this portal -http://www.genealogylinks.net/canada/all-canada/military.htm