Vendors typically send swag like coffee mugs, T-shirt, or cookies around the holidays to their valued customers. Nothing much but it's obviously an opportunity to gently ping the customer mid sales cycle. In the US, vendors typically take prospective customers (leads) out to above-average meals for business meetings. It's transparent but both the sales person and the prospect are getting a treat on the vendor's client entertainment budget. Would you say "no" out of rigid ethical purity or go along and still insist on more features, more due-diligence, more demos, and lower pricing?
You'll be embarrassing yourself in most western countries with the swag/gifts approach.