Another rule that has been coming up a bit lately is the Penatly Stroke. What is the threshold to call a PS or not? The main question, was the infrindgement going to stop a probably scoring of a goal, or was it intensional?

There are 2 components to this one. 

One Pager - umpires-corner-week12

RULE 12.4(A) — GOAL PREVENTION
A penalty stroke is awarded for an offence by a defender in the circle which prevents the probable scoring of a goal.
Intent is irrelevant — a failed tackle that removes a probable goal is still a stroke.

RULE 12.4(A) — GOAL PREVENTION
A penalty stroke is awarded for an offence by a defender in the circle which prevents the probable scoring of a goal.
Intent is irrelevant — a failed tackle that removes a probable goal is still a stroke.

THE ONE-LINE TEST
Did it stop a probable goal, or hit a player with clear possession, deliberately? Either one — stroke — whether it's a missed tackle, a deliberate grab, or a body simply in the way of the goal and no keeper there to stop it. However, No real chance denied, no deliberate act — play on or penalty corner.

GUARDRAIL — DON'T OVER-AWARD ON MARGINAL CONTACT
All three examples above earn a stroke because a real chance was genuinely denied or a player in clear possession was genuinely interfered with. That's a high bar, not a low one. A fair 50/50 contest for a loose ball with no clear possession, or a clean tackle that wins the ball before any contact with the player, stays a penalty corner at most — not a stroke. Ask which limb of 12.4 applies before signalling; vague contact in the circle is not automatically a stroke.