You have to claim a 3-time-rep OTB...so why not here as well?
this is not true. People say this sometimes, nut this is certainly wrong
No, it is correct. Read the rules.
"9.2 The game is drawn upon a correct claim by the player having the move, when the same position, for at least the third time (not necessarily by a repetition of moves): a. is about to appear, if he first writes his move on his scoresheet and declares to the arbiter his intention to make this move, or b. has just appeared, and the player claiming the draw has the move."
Can your flag fall when waiting for the TD or do they ignore this?