The reason why in a nutshell without getting into a ground school lesson that the 200 may become weight restricted it's because of its low max landing weight. The 200 has a max landing weight of 47k while also having the capacity to carry a huge payload for that type of aircraft. This means that we are weight restricted for take off due to our landing weight at our destination. Lots of times our max flight plan take off weight is way below out actuall structure max weight for take off. For example, the CRJ 700 is hardly ever weight restricted because it can land at a higher weight (67k). So, on a flight from DC to PHL , it can carry a full payload of people and bags and fuel for an alternate and still land within its 67k limit. But! That plane can carry a lot! Of fuel, if I remember right it's close to over 20k lbs. so ! If that plane was initially fueled for a flight DC to MCI with alternate fuel and suddenly it was swapped into a DC to PHL flight then the over fuel would cause it to become weight restricted unless they de-fuel it. Btw we also (CRJ200) have a ballast limit! There are things you can do to make it work "sometimes" like counting kids, or burning off fuel. But, if the fuel burn off required to get the jump onboard is a big number then it would not be practical and this is illegal to begin with.