I can understand that sometimes guests have no respect for your stuff. I had a guest who thought it would be funny to re-enact a scene from "Roadhouse" on my pool table, so I re-enacted a scene from "roadhouse", and launched him out the door by his neck.
I would stick with your acrylic. Its going to be a lot more resistant to any shenanigans. Yes it can scratch, but you can buff out scratches. Can't buff out a cracked glass tank and over 1000 pounds of water on your floor.
Either way, the tank isn't really built to handle getting damaged. Acrylic well get scratched from the chair repeatedly hitting it, and the glass won't really crack, but if it gets hit repeatedly, the movement of the glass will weaken the seals and the tank won't last that long.
I'd say get an old fashioned tank with the monster glass if you want something that can take abuse.