Notion of a "Slip Screen"
 

For the simple purpose of clarity, a "slip screen" is when the offensive player sets a screen and then as the dribbling team-mate approaches the screen, the screener prior to normal contact with the defender of the dribbler, quickly opens up/releases and rolls to the basket for a pass instead of remaining fixed on the spot where the screen was set. The hapless defender gets consequently "stuck" on the screener's back and cannot get around to guard the dribbler; this results in the reception of an easy short pass and a short distance 'try for goal' by said screener.
I considered this to be a clever legal offensive strategy. Well, one of my ref partners was trying to tell me that this was an illegal screen; I however disagreed and replied that this is a clever legal action and the onus is on the defense to countermand this stratagem--either by recognition for help defenders or the use of better footwork to maneuver around the "slip screen".
Have any of you observed the execution of such a described "slip screen" and adjudicated to the contrary? Jus curious, thanks.

Sometimes it's legal; sometimes it's not. IT depends on whether the official judges the move to be just a move to the basket or judges it to be a screening move (and there's ilelgal contact based on the rule).

"You can screen and roll, but you can't roll to screen"

If there is no contact between the screener and the defender, then the play is legal. If there is contact, then we must determine if the action qualifies as a legal moving screen (both players moving in the same path and direction) or an illegal screen (the screener isn’t stationary and the paths of the players are not the same or the screener has moved into the path of a moving opponent without allowing sufficient time and distance for the contact to be avoided).

Moving Screen ...
 

No way. At least not to thousands of fans in the cheap seats yelling, "Moving screen", over the past forty years.

From the Misunderstood Basketball Rules list:

A moving screen is not in and of itself a foul; illegal contact must occur for a foul to be called. If a blind screen is set on a stationary defender, the defender must be given one normal step to change direction, and attempt to avoid contact. If a screen is set on a moving defender, the defender gets a minimum of one step, and a maximum of two steps, depending on the speed, and distance of the defender. Players setting screens must have both feet inbounds.