"Capping" foleys only INCREASE likelihood of leaking, thru stoma, urethra, or both. The bladder wants to empty with the inserted foley, so when it's obstructed (or intentionally capped) it will try to force the urine out through any way possible to decrease risk of increasing AD and reflux.

In capping, you are increasing the risk of leaking or possibly causing it, and at the very least, you are exacerbating the leaking if you already leak.

An analogy would be -
certain foods give you heartburn, but you continue eating those foods and you take heartburn meds to help relieve the heartburn pain, so you can keep eating the foods that give you heartburn, and then take more pills to help the increasing heartburn... and so on.

Stop eating the foods that give you heartburn, you eliminate or DECREASE the need for heartburn pills.

Of course, neurogenic bladders aren't so simple or clear cut, but do you get the point?