A) did you even try before asking?
B) not a good idea. not in the slightest unless you have one or two as something just like "Hello, you are about to have an actualy important dialogue box when you click this". if the map lags at the start ,which happens A LOT, there will always be nubs spamming D D D D D and then when the lag stops they end up choosing like 5 things only pros do and lose the game b/c they were so busy hitting enter. like in the map Water War - Submerged you always have to tell people not to talk b/c a dialogue box pops up within like 5 seconds. some ways around this are having in-game warnings not to talk pop up a few seconds ahead or set up a few extra dialogue boxes just to cushion the fall from when they stop spamming D D D