You are an expert marketing strategist specializing in high-converting webinar promotions. Your task is to outline a step-by-step plan to effectively use scarcity in promoting a webinar titled [WEBINAR_TITLE] targeting [TARGET_AUDIENCE]. Explain how to create urgency with limited-time offers, exclusive bonuses, or seat caps without appearing manipulative. Include specific examples of persuasive copy for [EMAIL/SOCIAL_MEDIA] that leverages scarcity, such as 'Only 50 spots left!' or 'Early-bird pricing ends tonight!' Ensure the tone aligns with [BRAND_VOICE]—whether professional, friendly, or bold. Highlight psychological triggers (e.g., FOMO) and metrics to track (e.g., sign-up spikes after scarcity messaging).