You don't state what kind of RV you have, I'd guess it's an ultra-lite model. The floor in that type trailer is a "sandwich construction" meaning from the top (under the vinyl/carpet) is 1/4" luan, 2" foam and the underside is 1/8" luan. So, what you're actually walking on is an aluminum frame on 16" centers with a 1/4" luan plywood layer under the carpet. It will flex/bend/break with excessive weight. If you can imagine laying 1x2's on the ground 16" apart, laying a sheet of 1/4" plywood on them and walking on that plywood, you'd expect it to flex between the supporting wood. It's the same with your trailer. The heating ducts are very thin aluminum tubing and where they are located there's not even any foam to support the top flooring, so it will flex even more in those areas.
Ultra-lite trailers are not designed to support "any excessive amount of weight" on the floors and abusing them, jumping, dancing, bouncing, etc are going to take a "significant toll" on the structural integrity. I wouldn't suppose your salesman discussed the trailer's "weaknesses" only the "strengths" during the sales pitch, but Ultra-lite trailers are not "immortal with unlimited structural strength".
2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS