Originally Posted by LupineChemist

In the fast track immigration in T5 on Monday, there was a family doing a separate ticket connection that was almost certainly going to miss their flight and would have been completely avoidable with checking through. A 45 minute delay combined with nearly an hour in fast track (that alone should be a major issue) and a T5 -> T3 transfer meant they were in trouble when it would have been very reasonable with a through checked bag where you get the direct coach to T3 and avoid the immigration mess.