Spliced!

Is it normal to have a splice in the middle of a ball of commercially prepared yarn? I don't think so or why else would you buy a certain size ball? Well imagine my chagrin when I was about halfway thru' my ball of angora/merino as I was knitting my scarf when there appeared a tied knot...an obvious splice. This wasn't exactly a cheap ball of yarn either. My scarf does not lend itself to easy invisible weaving in either. Does anyone have any good techniques for weaving in ends in a lace pattern? I already have one splice as I went from one ball to the other.