Translation:Please check your luggage.
It is not wrong; 一下 softens the tone of the sentence, making it sound less like a command. It could also mean "to do a quick check", although the former makes more sense without context seeing as it can come across as a command, or at least instruction, even with the character 请 in it.
I second this. I got this wrong because I put "baggage" instead of "luggage".
There is a bug here, it just gave the correct translation as "please cheque your luggage."
This has two meanings in english. Does the Chinese sentence say to inpect your luggage, or to ask the airline to put it in the cargo of the plane?