This is not so.
In this situation, if the ball carrier can get a knee to the ground, the maul still continues until either the ball emerges, becomes unplayable, or the maul collapses – in which case there would be a scrum awarded to the team that didn't have the ball at the maul's commencement.
A tackle is effected when a ball-carrier is held and brought to the ground.
Being brought to the ground means that the ball-carrier is lying, sitting, or has at least one knee on the ground, or he is on another player who is on the ground.
If one or more of the opponents also go to ground they are considered to be "tacklers" and have certain requirements.
Opponents who are on their feet and holding the tackled player are not considered tacklers and they have other obligations.
Firstly, the tackler must immediately release the ball and the tackled player, before rolling away.
This should be done in an "east – west" direction, away from the tackled player and not into the opponents' side of the area.
Otherwise, the tackler can immediately get to his feet, turn so he is facing the opponents' goal-line, and can attempt to play the ball provided a ruck has not formed.
If there are no other players at the tackle, the tackler can then use his hands to win the ball.
In a trial law amendment for this season, as soon as the tackler gets back to his feet and gets his hands on the ball, a ruck is considered to have occurred and offside lines are created at the hindmost foot of the last player's feet on each side.
All other arriving players must then enter the ruck from behind their offside line – "through the gate", not from the side.
Opposing players in the tackle who stay on their feet must immediately release the ball-carrier – which must be clear and obvious to the referee.
They may also then play the ball, provided they have turned to face their opponents' goal line and a ruck has not been formed.
The tackled player – on the ground – must "immediately" do one of three things.
He must release the ball so that is available for play to continue, he can play the ball by placing or pushing it on the ground in any direction, or he can pass the ball to a team mate on his feet.
The player must then move away from the ball or get up.
He should ensure he is not lying on the ball, neither near or over it, nor should he prevent an opponent from gaining possession.
All arriving players must endeavour to stay on their feet so that they are supporting their body weight.
That means they cannot put their hands on players lying on the ground or the ground beyond they ball.
All this sounds clear and simple – what could possibly go wrong?
From a referee's perspective, the first thing to look for is whether the tackler or those opponents holding the tackled player clearly release him and the ball.
Then, whether the tackled player releases the ball and plays it legally and moves away or gets up.
The next thing to address is what the arriving players should do.
We know what they should be doing in rugby law – staying on their feet and supporting their own weight.
But rugby is a contest for the ball, and the carrier's team will be trying desperately to protect the ball and their players on the ground.
The opponents will also be trying to gain possession of the ball and/or move opponents away from it.
Teammates of the ball-carrier who enter the tackle area or the post-tackle ruck should not be draping themselves over the tackled player who is still holding the ball while stationary.
Nor should they be going to ground with their hands or their bodies beyond the ball, thereby effectively sealing it off so opponents cannot get at it.
Opponents may try to move players of the ball-carrier's team by "cleaning out" with a low-to-high action, but this can only be done to players involved in the post-tackle ruck.
They cannot do so away from the ruck, thereby creating a hole for their team to run into, should they gain possession.
The critical point to look for is which team is under pressure and therefore more likely to infringe – in order to keep or gain the ball.
These days, if the tackling team don't have many players involved in the tackle and post-tackle situation, they tend not to compete for the ball and fan out in a defensive line.
But if the ball-carrier's team don't have the numbers to ensure they keep possession after the tackle, they will be the team under pressure and more likely to infringe.
Either way, the tackle and post-tackle play is a high work-rate area for referees.