Right now, the anti-gold funneling penalty can cause the jungler to receive 10g less gold from each lane minion, and that penalty is not removed until they complete an enchantment on their jungle item.
The problem is, not every jungler "has" to complete a jungle item. Almost every jungler does. But there are a few junglers who can skip doing that. For example, Tryndamere doesn't use mana, so sometimes he simply buys only the Machete and nothing else. There's also a few junglers who may sell their jungle item early.
My team was shoved into our base and our inhibs were down. It was well past 20 minutes into the game. I was a hyper carry jungler, so I was taking all the big waves that were crashing in. Suddenly I realized I was getting 4g from the caster minions, and I was like "Oh crap!".
I think the gold funneling problem is more of a "laning phase" issue. And past the 20 minute mark, or possibly even as early as 14 minute (when turret plating falls), it should not be a problem anymore. Once players are grouping as 5 and pushing lanes together, the jungler should be allowed to take the lane CS at that point, without penalty, because he's now grouping with his allies on extended sieges.
I think Riot should modify the anti-funneling penality so that it is automatically lifted after a certain number of minutes into the game, either 14 minutes or 20 minutes, whichever seems best.
Also, special logic should be added so that if any inhib falls, the gold funneling penality should be instantly lifted, even if somehow it is earlier than 14 minutes into the game. Definitely if an inhib is down and the jungler is helping to clear the waves to save the base, that should definitely not be considered "gold funneling". It probably wouldn't be necessarily to include this special logic in the item's tooltip, just remove the penalty if an inhib falls on either side.