No Warm Up is usually 20 minutes.
I cant figure out why it would be bizarre for someone to see other martial art equipment on the wall considering that many BJJ schools are run out of other Martial Art school.
Sometimes we warm up doing Takedown Drills, Guard Passing Drills, etc. But we always dedicate at least 20 minutes to a good Warm Up for several reasons. The first being that not everyone who trains has time to train outside the dojo (i.e. the gym) so we want to give people as much of a workout as possible including a thorough warm up, drills, technique, and finally stretching and cool down. I think this is what every school should have.
Of course people pay for BJJ and not just working out. However, BJJ requires a lot muscular endurance, range of motion, explosiveness, and as you get better, mental toughness. Is this lost of anyone here? I would think everyone who has trained for a while would think similarly. Dont worry we work on plenty of techniques. We incorporate a lot of Sambo and Judo in our BJJ classes. Be on the lookout and you will see some of our Takedown drills!