I use two characters on different computers and different accounts for t-maps; one to dig up the map and one to kill the spawn. On Eiffel Island I found that occasionally my t-hunter could hide using the hiding skill and the character would be perfectly visible to my tamer. The t-hunter goes that grayish shade when hiding so I know I have used the skill successfully as I should at 100. I saw some posts a while back about people that were being attacked when hidden during PvP. Everyone at the time cried "exploit" but it seems there is a simple bug that makes this possible.