I disagree; I put upcoming shows on my resume as long as I have a fully signed contract for the show. Sometimes an SM is contracted one year or more in advance (common in larger theatres). The theatre is reserving your services for the time period of the contract, and to withhold this information while courting other jobs might lead you into a sticky situation. Actually, if SMing is all you do, it's ideal to book your shows at least 6 months in advance to keep your income steady. Yes, things change, shows are cancelled, dates are adjusted. But a signed contract means you're on board to do a show. Putting this on your resume shows you have a serious (and busy) career, and that you honor your obligations.