I wouldnt have tipped. That said, as a guest to the country and at a work gathering you may want to tip just to not leave a bad impression of yourself.
Well yes, obviously we tipped at the end, but I was just surprised that everyone in our group was unhappy with the entire service and food, yet we still had to top. There is a saying where I'm from "co kraj to obyczaj" - "every country has its customs". That custom just stood out for me.
hmm if it was a large party, generally you are obligated to tip and they already include it on the receipt. Be especially careful not to tip twice in these cases. Though I think that's insane, but I guess large groups have a reputation of stiffing wait staff.