Just saw Spurs great 3rd goal! ...ruled out

[Karl]

Should referees make sure the ball is placed on the corner line for corner kicks?

No!
Referees duty is to make such the ball is place as per Rules of the Game and Regulations coving same.

Note: The lines of boundary are considered part of that boundary = the whole of ball has to be outside of the boundaries for the designated area from which corners are to be taken before the referees should interfere in so far as placement of the ball previous to the kick being taken is concerned.

Surely that is the reason behind no offside calls...,one can't be on the field and be ahead of the kicker.

No so!
It is a designation of the Law.

As fact a striker could be nearer the goal-line than the ball. It all depends on where the ball was placed before the 'corner' was taken and also where the kicker was standing as he struck the ball=played the ball.

Example: "Skill" Cole at times placed the ball furthest from goal-line within the allotted area from which a corner-kick was taken and approached the ball from even further away from the touch-line to take an "out-swinging corner-kick". On other occasions "Skill" approached on a path parallel to the goal-line whereon he struck the ball with the outside of the foot for an "in-swinging corner-kick".

Would you start Chamberlain tomorrow?

Yes!
...a fast start is important but more so having 11 on defense when needed. As Jose Mourinho would say, *"No room for baggage (on defense)".

*...and thus Matta out! ...and Oscar who was lousy on defense has become a tiger on defense.

[Rockman]

Should referees make sure the ball is placed on the corner line for corner kicks?
Surely that is the reason behind no offside calls...,one can't be on the field and be ahead of the kicker.

Would you start Chamberlain tomorrow?

[Karl]

by a wrong call.

Cannot be off-side in your own half of the field...PERIOD! That ball was played with the player ae in his own half of the field.

Another one that catches out some - You cannot be off-side if at the moment the ball was played to you by your TEAM-mate you it was nearer opponents goal that you were. This sets up a possible scenario whereon the entire attacking TEAM is near to the opponents goal when the ball is played...just about improbable! ...but in theory it could happen.

Then there are the special cases - Cannot be offside directly from - Thrown-in, Corner or Goal-kick.