This is not meant to cause offence, but I don't understand the problem some people have with 'sales'. Selling add-ons is not unethical, it happens in almost every industry, and there's nothing to say you might be offering something the customer hadn't thought of, but is quite keen on.
You book a holiday, they offer you insurance. You take car insurance, they offer you breakdown cover. You buy a car, they offer you Supagard, Insurances, Warranties. You open a bank account, they offer you loans, credit cards. You pay for your shopping, they offer you cashback.
Yes it's purpose for the vendor is increasing profits, but not every customer hates it. There's a difference between a good sales pitch and a hard sell. I've been in sales all my career thus far, and have never made anyone buy something they don't want - the success comes from making them realise they want something when they didn't realise previously.
Offering extra rooms, stain protection, upholstery cleaning while your with the customer is not bad practise - it's offering a service (as long as you know how to take a 'No') - it's not Bait & Switch.
Or thats my 2p worth anyway..
Regards,
Ash