Question on obstruction

[dsimp8]

ASA rules please......Two situations:

1)BR hits ball into the gap and while rounding 1B,he is obstructed by the 1Bman. .I would put my arm out for the obstruction call. Not seeing this the BR takes a few steps towards 2B then decides to go back to 1B. Do you put him on 2B or did he give up the right to go to 2B by returning to 1B.

2) Rundown between 1B and 2B. The runner runs into the infielder (not intentionally) trying to return to 1B. Don;t you immeadiatly call "time" and put him on 1B or do you let the play continue? If he turns to go back to 2B(if you let the play continue)do you drop your arm since he gave up the right to go back to 1B on the obstruction call?