So.. my dilemma is that my FMIL is catering our reception and is getting a friend and friend of her daughter's to 'serve'. They are covering the food, etc. as their gift to us, so we are not paying for food or servers. My question is.. do we need to tip the two 'servers'? I'm fairly certain they are not being paid by my FMIL to help out. And if so, what is a good amount for a 3 hr cocktail & appetizers reception?