This is a great clip of why it’s not a double hit but it doesn’t show the difference between a legal shot into a frozen ball and an illegal push shot. Lots of people apparently (including Karl Boyes it seems) think it’s a push. Do you know of a clip showing the actual illegal push technique?
Here are several. The first 3 links are different views of the same shot involving an illegal push stroke. The fourth link is an illegal push stroke on a different shot and there are tons of videos online with other variations of this shot (where they make different balls of the three depending on the exact setup and which english they used in their illegal push) but I don't know where they are off hand, maybe somebody else can post some of them.
Another very famous trick shot using an illegal push that is out there all over the place, but where I don't have a link offhand, is where say the 8 ball is frozen to the rail less than a diamond from the corner pocket, and the cue ball is frozen to the 8 in a line perpendicular to the rail, and then you push the cue ball with english and the 8 ball goes "sideways" along the rail into that near corner pocket. Maybe somebody knows a link for that one as well.
On a side note, it is near if not impossible to hit hard (where the cue is already clearly moving fast prior to impacting the cue ball) and do a push shot, because a push essentially requires first somewhat gently placing the tip against the cue ball and then pushing so that they stay in contact with each other for a prolonged period. With some practice someone can somewhat mask this action on softer shots to almost make it look like a normal stroke if somebody is not paying close attention to the stroke, but that isn't really possible for them to do on hard hit shots. Pongers hit hard on this shot so you can all but rule out the possibility of a push just based on the speed of the hit alone. The shot that Pongers did here was very clearly a normal, legal stroke, not a push, and as such was not a foul if the balls had been declared frozen by the ref.
