The worst outcome in this whole category is a heavily loaned policy that lapses. The loan gets treated as a distribution, the gain becomes taxable income all at once, and there's no cash left to pay the bill because you spent it years ago.

Overloan protection is the rider built to prevent that specific ending. When the loan balance climbs to a defined percentage of cash value, the rider triggers, the policy converts to a paid-up status, no further premiums are due and no further loans are allowed, and the contract stays in force until death so the loan is settled out of the death benefit rather than by a lapse. No lapse means no taxable event.

It comes with conditions, and they're specific to each contract. Typical ones: the insured has to be past a stated age, often 65 or 75. The policy has to have been in force a minimum number of years. The loan has to exceed a threshold relative to cash value. There's a one-time charge when it triggers, sometimes a meaningful percentage of account value. And once it fires it's generally permanent, so the policy stops being a flexible tool that day.

Some carriers include it, some charge for it, and some don't offer it at all. Here's the thing though. It's not automatic even when it's included. On several contracts you or your beneficiary has to elect it, which means somebody has to be paying attention at exactly the moment nobody is.

So treat it as the airbag rather than the plan. It exists for the case where the borrowing strategy ran longer or hotter than intended. The actual plan is not to get there: keep the loan-to-value in a range you'd be comfortable defending, run an in-force illustration every year or two rather than every decade, and know the number at which the rider would trip on your contract.

Tax treatment here is specific to your situation and I'm a licensed insurance broker rather than a CPA, so get a tax professional in the room before you build a plan around heavy borrowing. Ask your carrier two questions in the meantime: does my contract have this rider, and do I or my beneficiary have to elect it.