Of course you know to do this, and waiting to get to the table is not inappropriate. However, you would be amazed at how many people will get right to the walk through and ask if they need to take it out. The announcement to do so is an attempt to prevent this as it slows everyone else down. Since you are a seasoned traveller, just take it in stride that not everyone else is and let it go. Getting upset about it is a waste of brain power and I am sure you have better things to concern yourself with.

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Don't take life too seriously, afterall, you won't get out alive.