* You have to work with an, at best, passive team, at worst, actively hostile team. * You need to work against very tight deadlines and a lot of pressure in a codebase that you know nothing about, and need to ramp up in quickly.
* You spent weeks (months?) developing expertise in a system you will probably never work again.
It is a terrible idea, but to be honest I can't think of another way to deal with the problem that it is trying to solve (mismatch between agendas of different teams).