When administrating an end line throw-in from the front court, remember that you have an option of being on the inside of the thrower or boxing the thrower in by being on the outside of the thrower. You have that option because the trail official has sideline responsibility and also deep corner responsibility as well.
I suggest you examine the option of being on the inside of the thrower carefully. Many teams have designed plays for when they have a throw in from their own baseline in the front court.
Many of these designed plays have as their first option a pass into the paint, often to their tallest player. These plays often involve screens and rolls off of those screens designed to get the ball to a teammate in the middle of the lane.
Officials who align themselves on the inside of the thrower may have a better view of the action in the paint on these throw-in plays.
Some officials only go on the inside if the throw-in spot is well outside the lane area. I am suggesting that even if the designated spot is on the lane line an official can align himself on the inside of the thrower and hand the ball, step back a little to be out of any passing lanes and have a great look at the paint area should the throw-in go that way. This inside position also allows for a timely rotation if the results of the throw-in call for one.
The clip below shows an out of bounds play where the lead may have had a better view of the action had he been on the inside of the thrower.