I encountered that last time I rented from Alamo at DFW as well, I was getting quite pissed at the guy at the counter. He at one point, after starting the process of the rental, tried to guide me to the kiosks instead. The annoying part was two-fold - I was the only person in the checkout area at the time so it's not like he had anyone else to help - and the kiosks were actually down at the time.
If the kiosks are working, the easy way to avoid the high pressure tactics is just to use the kiosks. I normally do use the kiosks at Alamo, and it makes it easy.
No issues with the return in that case at all for me.