sterilised cover slips

do cover slips stay sterile if you sterilise them under the hood, place in a 12-well dish for example, and then take out of the hood with the dish lid on?

i do this often with my PhD supervisor when he needs cover slips preparing and i leave them on his bench for him, which he told me to do. But I sterilised some for a post-doc in the lab and she looked at me in horror when i asked if I should leave them on her bench for her, and told me I should just be leaving them in the hood.

is this just a matter of personal preference or do i need to stop leaving sterilised cover slips out on the bench?

(note: sterilise in this case just means dipped in ethanol and passed through a flame.)