As a player in a D&D 5e campaign, our party was presented with a battlefield with several different environmental features (in this case, a goblin cave entrance with an alarm system and two watchtowers). We ended up planning and deliberating how to approach this for about 15-20 minutes before deciding to stealth along the cliff and disable the alarm. During the planning, some players were getting in to it and enjoying the discussion, but others tuned out after about 10 minutes or so.
After the session, we all agreed that we probably spent too much time planning our approach. The DM was a bit frustrated with it, and suggested that next time there might be in-game consequences - "the goblins see you" or something to that effect. Is this a reasonable line of action, or should only social pressure be used to speed up planning? Or some other approach?