When you're starting out and running your first 10 loads, you'll get into a rhythm with detention. As a refresher: detention is a fee a trucking company can charge a broker if a shipper or receiver holds their truck too long to get loaded or unloaded — essentially, "loss of use of time." Time is money.
But what if your driver arrives at the shipper 5 minutes past the appointment time? Nine times out of ten, the truck gets marked "Missed Appointment Time," and doesn't qualify for detention at all — even if you then wait 5+ hours to get loaded. The carrier agreed to the Rate Con's instructions, and arriving late means you're not abiding by the contract. The broker is within their rights to deny detention pay in that case.
But it's not the end of the world — most shippers take less than 2 hours to load or unload. If it takes longer, it's either a poorly managed warehouse or a busy one. If you're only 5-15 minutes late, you can always politely ask whoever's checking you in if they can adjust the times on the BOL or POD. 95% of the time they won't, but it never hurts to ask. What you should never do is personally scratch out or change the arrival/departure times yourself — that's a guaranteed way to get blacklisted, written up on Carrier411, and potentially dropped by your freight factor. The moral of the story: just arrive early so you don't have to deal with any of this.