Two-blocked for 8 years before a spotter called it out

I ran a 50 ton Link-Belt for almost a decade and never once thought about my tagline placement on the hook block. Then a new guy on the ground yelled up that my ball was riding too high and I was asking for a two-block. He was right. I checked the load cell and I had been running about 18 inches of slack the whole time. That mistake eats cable and adds stress to the boom. Now I set the limit switch tighter and listen when a spotter questions my setup. How many of you trust your anti two-block gear over a visual check, or do you always look at the hook before lifting? Is the tech making us lazy or is it a backup for guys like me who got too comfortable?