When you are arranging a seminar in an external location, such as a hotel, be aware of room size, layout and lighting because these aspects can make a difference.
It’s one thing to see a room well lit, with no people in the room, no projector, no speaker, no presentation. Only on the day of the event, when the presentation starts, will you see the problems.
A long and narrow room, like the one in the photograph, with lights dimmed and a hidden presenter is not a good setup.
People in the back will have a hard time following the event because of heads blocking the view, no view of the speaker and low lights that easily put one to sleep or invite smartphone activities.
Check the lights: can you turn on/off various lights in the room to make sure the speaker is always seen when speaking? If you need to show a video, can you darken the room just during its projection?