The service charge thing is really something in the BVI's..as there is no tax on food you will sometimes see it as a tax as a trick to get you to add service.I look at the bill..I ask if the server gets the tip as some places the owners grab it. If there is nothing added I give 20% at least.If they add some I round it up to that.I always try to tip in cash so it goes in the server's pocket..