The reason many students who start as an engineering major but switch is because of the difficulty of the curriculum. This change takes place at all schools not just those who think they want to pursue the combined engineering program. And this change takes place mostly in the freshman and sophomore years. If a student can get through Calculus I - IV, Differential Equations, Linear Algebra, Physics I and II, Chem I, and Comp Sci, there isn’t much else engineering can throw at that student to deter them. By the time a student is done with all these foundational courses they will know whether engineering is for them or not.