This is primarily if you will be trying to get the trinket alone, i.e. no 70 helping you.
What you need:
1. Gnomish Mind Control Cap
2. Patience
3. Luck
What you need to do:
1. Go as early in the morning as you can, it goes off at 3 am,6 am, 9 am and a lot of times least crowded at these hours.
2. If you see a high level character of the opposing faction, hide or go stealth, so you dont die before you even get to run in there.
3. Wait-- see if any one else comes to contest the 70 thats there already.
4a. If there is another high level there, wait for those 2 to battle out and 1 to die
4b. If it is only one high level character, thats the goal, you should be in the clear.
5. When you see him walking down into the arena, you need to run in and use the mind control cap; this will be tricky but you can work the timing out, make sure to stand up on the stairs so they cant get to you easily.
6. Once you have control of the high level, run him as far up out of the arena as possible, you wont have much time, but just try.
7. SPRINT to the chest and loot is asap.
I know there is lots of room for failure here, its just what i used to do when i couldnt get any guildies to help me in STV. You dont have to use this guide, its just a little tip that worked for me before, so im just trying to help. I know how long that thing takes to get so GL-- its worth it.
P.S.-- if its a 70 of your faction, you can ask him this: can I buy the trinket for like 10g since the thing doesnt sell for that much in the first place, well both win. If they say yes; invite them to group say: okay im going to loot it first, and give you the cash when i have trinket. If you get this far, just loot the thing and log out, the worst that could happen is that they will just kill you which your used to anyway.