May eventually lead to someone testing this out on something else totally unrelated to this and producing results.
Figured this out back in march 2005.
Was on my druid at the time grinding in winterspring. Had just finished my second turn in for the winterspring frostsaber mount. When someone else had showed up and was upset by the amount of quests involved. He attacked the quest giver and my mouse was happened to be highlighted over the quest giver at the time, soon as the quest giver moved, my mouse icon showed a bag(trade) icon. He then proceeded to kill him but that bag icon had got me curious.
Few hours later got a friend to help me out, had tried attacking him myself but had to be at war to attack and wouldn't get bag icon. About 30 mins later we had both purchased a winterspring tiger each. The trick was to get a friend to stand next to him and attack his pet, the second he would start to attack, you would have to click on him to open his stock window(bag icon would show up) and sitting in his window was tiger available for purchase.
Still have the druid and the mount to this day. Rep is still at hated!!