When pool swimming, a crowded lane can make it difficult to avoid stopping or changing strokes due to other swimmers. Generally, swimming etiquette dictates that the swimmers pass one another at the end of the lane, rather than in the middle. If this etiquette is adhered to, then the lane traffic will not impact accuracy of the swim data on the watch.
However, if etiquette is not adhered to, the following actions can cause extra lengths to be counted:
When catching up to a slower swimmer before the end of the length and the pool is shallow enough, it is best to stop swimming and walk the last few meters to the wall, if possible. The device will interpret this as a long turn and the length count will still be accurate.
If walking is not an option, which may cause a stroke change, when catching up to another swimmer, press Pause before switching to breaststroke. Remember to un-pause as you push off the wall into your long streamlining (glide) phase. This action will break the swim interval into two intervals, however, the total distance for both intervals and the entire swim will remain accurate.