Hahaha. Thanks for reminding me of the first three rules of Stars!: test it, test it, and test it again. I set up a test and all the results fit exactly with fields operating like scanners. I tripled the number of trials and now it looks like the first set of tests was just extremely lucky. I can confirm that a 70% cloak ship can remain undetected 1 ly from center of a 100 ly field and the same can be detected 83 ly from center of the same field.