Let’s consider the Line of Play (LoP). This can’t really be a complete discussion without understanding the Lie, but we’ll go to that topic a little later as most have a pretty good understanding (you should – it’s basic to the game). We’ve observed more misunderstanding about LoP, so let’s go there first…
LoP is defined in Lie 802.05.D as, “…the imaginary line on the playing surface extending from the center (sic) of the target through and beyond the center (sic) of the marker disc.”
My throw landed just short of a mando tree, but on the wrong side, but hasn’t passed the mando line. I can step to the side such that my supporting foot is no closer to the target than the lie, which allows me to throw comfortably around the mando. Can I do this?
No. If the normal LoP crosses the mandatory line, then the mando becomes the target for application of LoP for that throw (Prohibited Route 804.02), and your supporting foot can be no closer to the mando than your lie. See diag A1 following.
My tee shot has gone OB, and the location it passed the OB line is behind a tree. As I can’t be penalised again for an optional lie, can I go back on the LoP to establish a new lie?
Yes, but as your LoP is from your disc to the target, with taking your 1 metre relief there may be little room to gain benefit, depending on the angle of the OB line, as you must throw with all supporting points in-bounds. See diag A2 following.
It has been noted that some players have interpreted the line of play to mean the line of flight from the tee (or previous lie) to where the disc went OB, but this is incorrect. If you can gain no benefit going back on the LoP, the other option is to re-tee (or return to the previous lie) for no further penalty.
Link to the rules: https://www.pdga.com/rules/official-rules-disc-golf