The short answer is “all the time”.
The example is of course set by our professionals who bend every rule in the book at every opportunity which in turn makes the referees job much harder than it need be.
The game begins with the kick off and the rule is clear that every player must be IN HIS OWN HALF but the player receiving the ball from the kicker usually has at least one foot in the opponents half, sometimes both, just to make it easier to pass the ball back to a midfielder. The kick should of course be retaken but seldom is.
Next we have the touchline dancer who tries to gain an advantage by a little dance up the touchline when taking the throw in. The law is quite clear that the restart takes place from where the ball crossed the line. At the referees discretion and because it is not always possible to be precise, a yard here or there is allowed but not up to half the pitch. Players are not just guilty of dancing up the line as some pick the ball up when it has crossed the line and throw it forward to a mate several yards up the line to gain ground unfairly.
A corner kick requires the ball to touch part of the quadrant prior to the flag kick but players regularly try to place the ball on a more favourable lie just outside the quarter circle.
The law covering free kicks also clearly states that the kick will be taken from the spot where the infringement took place and not as often happens where the ball has landed after the whistle blows. Because of the ebb and flow of the game referees will normally be content if the ball is returned to the area where the foul was committed but again the advantage takers will restart from as far up the park as they can get away with.
The law leaves no doubt that the ball must be stationary when the kick is taken and to be honest anybody who restarts the play with a moving ball free kick on the pretext that they just want to get on with the game is not kidding anybody. To steady the ball before the kick takes but a couple of seconds.
In my day if you held off an opponent without making any attempt to play the ball,even though you could, it was called obstruction, and you conceded a free kick. There was no keeping your body between opponent and ball in order to gain a goal kick. The only time you got away with that was when the ball was about to cross the line and you allowed it to run out. Any use of body weight to hold a man off for several yards was not on and pundits and commentators alike give the wrong impression by trying to justify it as “the use of upper body strength”.
Shoulder charging was permitted but the impact had to be shoulder to shoulder when the ball was within playing distance of both players. Using your shoulder to charge an opponent in the back or well away from the ball was and still is a foul.
The current practise of using your arms to hold off opponents in a foot race for the ball was not on and neither was pulling people out of the way with a hand on the shoulder,or by tugging jerseys or shorts.
However, the really dangerous activity that has been allowed to develop is the use of the arms to gain leverage when jumping for the ball. In my day you used your leg muscles to jump and nothing else.This theory that you should be allowed to use leverage should be banned as it would save many a broken nose or visits to the dentist, not to mention concussion and neck injuries with the forearm in the back of the head.
Football has changed but most of the laws are much as they ever were apart from the offside which should never have been changed to it’s present format. Allowing the forward to be level with the defender when the ball is kicked is fine but I have yet to be convinced that any player who is in an offside position in the penalty area is not trying to gain an advantage. Why else would he be there? Time to go back to the straightforward rule that a player is offside when the ball is kicked unless there is more than one defender between him and the goal. The operative phrase is “when the ball is kicked” which means that coming off a defender does not apply because the ball must have been kicked before it struck the defender. As the meerkat says “simple”.
It is unfortunate that the game has been allowed to go along this path but if the much maligned officials tried to put matters right they would be slaughtered by the press, the commentators and the pundits, none of whom really know the rules.