Originally Posted by: Jolly McJollysonThe short answer: No, that's not true.

I'd have gone the other way. The short answer is, yes it is true....

The more notes (or probably more appropriately, intervals) that are in use, the more likely it is that what you are playing will clash with what someone else is playing.

In practice, it's unlikely you'll both hit the right/wrong notes at the same time as Jolly says, but it's all about how much you want to have to think. It's things like this that separate the lead playing men from the boys so to speak... not just staying in one position the whole time, but moving around to pick up on different nuances as the underlying chords / bassline / whatever move along. Knowing which intervals are compatible and which sound like nails down a blackboard is a useful skill...