This may be the case, especially if everyone else is playing well in their given positions. However, if there is the possibility of a swap, then it should have been thought out to a degree on the training ground. It has to be practised in challenge games and all players made aware of the fact that such swaps are being rehearsed because they might be needed in the game proper. Having a talk about tactics prior to a game will have very little effect on team performance if those tactics have not been practised repeatedly during training sessions. We often fail to understand that much of what we tell players is forgotten when the game starts.
Players always return to their instincts when under pressure.
If we have worked to develop the right instincts then the tactics have a real chance. The coaching response is often to increase the amount of physical fitness training for that player. This may work to a degree, but it will never solve the problem fully. The right level of muscle fuel is linked to what and when a player eats and drinks. Play the Position' is a game which limits player movement in order to give the coach the time and space needed to develop their positional skills as well as their technical skills.