Did this dealership sabotage my vehicle?

I recently brought my vehicle in for servicing at my local dealership. When they were done, they asked me if I wanted to dish out a ridiculous amount of money for something I could do myself so I declined. A few minutes later, I had paid and was out the door. When I got home, I found out that my rear passenger side brake hose had been damaged and was leaking brake fluid. Obviously this would have been something they would have found and told me but I'm thinking they did the damage themselves after I refused in hopes that I would come back to them to fix it as well as pay for the other thing. Am I just paranoid or is this a real possibility?