Another idea is to buy some warning stickers that you put over the flap. It would have to be torn to get into the cabin air filter area. I used these for mine and put three of them on there. If you break the three stickers you are a complete idiot IMO.
Do Not Touch Sticker - (Pack of 12) 6" Large Round Laminated Vinyl Decals Sign Warning Labels https://a.co/d/4RDDjt6
Do Not Touch Sticker - (Pack of 12) 6" Large Round Laminated Vinyl Decals Sign Warning Labels https://a.co/d/4RDDjt6