Two weird situations observed yesterday.

No personal involvement here but being a keen naturalist and observer of the world i noticed two Golf Rules possible predicaments yesterday on the course.

First was 'in a sand bunker'. Maybe in.  Lots of porous rock, even large solid termite mounds around here and this bunker face was rocky with holes big enough for a one pound coffee can to get through. What if a ball runs into the sand and proceeds to roll into the hole. I know grass in the bunker is 'not in bunker' if ball on grass.  I thought if ball went into hole in wall of bunker face, what to do.  Is ball in bunker? Free relief? To where?  I would have called ball not in bunker, in termite mound, drop outside of bunker no closer to hole.

2nd deal was a plastic liner along inner edge of cup in green.  When i putted out i did not see problem as liner was below lip of hole on my side. But from opposite side i saw the liner up, extending above green about 1/4 inch. If i had been faced with this situation on my putt, could i have replaced the liner to its proper place, below, or equal to, the green surface, and then putted out without penalty?  Penalty coz can't touch green except in certain cases.  I would have called 'greenskeeper equipment failure' and fixed, then putted, no penalty.

if the ball is on the non-grass face of the bunker, it is in the bunker.  If it is in a hole between rocks on that face, you either play it or deem it unplayable.  If you deem it unplayable you must drop it no nearer the hole within 2 club lengths or back on the line from the hole through where the ball lay within the bunker or play from  where you played your previous shot.  One stroke penalty for any of those options.

If the ball is in the bunker and there is interference to lie, stance or line of intended swing from a termite mound, you may take relief without penalty within the bunker, up to  1 clublength form the nearest point of relief.  If necessary, because you are in a bunker, you may take maximum available relief i.e. you are not stuck if full relief isn't possible.  You may also take relief under a penalty stroke where you played your previous shot (stroke and distance).

Decision 16/4 tells us that we should report a hole liner that is not sunk deeply enough but is below the rim of the hole and carry on playing.  It does not,however, deal with one that is projecting above the hole and so how to deal with that?   My view is that the liner is an obstruction and so you can, if it is movable, push it down into the hole if possible or even pull it out. Remember, however, it is only a movable obstruction if it can be moved without causing damage, Touching your line of putt while moving an obstruction is not penalised ( Rule 16-1a).  If it cannot be moved and is only partially affecting the hole, you could take relief from its intervention on your line of putt.  If it is completely blocking the hole and cannot be moved, you are stymied  until you can get someone along to fix it.