Do you think i will get caught with my moped?

My grandma doesn't want me to use a moped i just bought but i think i could leave it at a marina really close to me. My brother and i have to share a car and work in opposite directions so it would be very convenient to use it. We start work at the same time so we would both drive to the moped and then go to work from there. I've never run into my grandma on the road and i have been working here for 4 years. My grandma would be very mad if she found out and would probably not want us to continue coming down to her summer house in the summers. I am 20 and my brother is 18.