Gena, warnings are useful for sellers as they provide some assistance to you if someone complains or sues you. Do not shy away from providing proper instructions and warnings. The last thing you want is someone to slip over on the shower because of your product, especially when you had the opportunity to warn them but didn’t. People will appreciate you being professional and making the effort to give them proper instructions and warnings. So, I would not worry about scaring people away – I doubt if it would.
Also, it doesn’t need to slow sales anyway. People buy your Amazon listing. They only see all sides of your packaging and the inserts after they have bought it.
PS My products have all sorts of warnings and instructions in the listing, packaging, inserts, emails, etc.