should I be concerned with extra people at my property?

[Autumn G.]

I am a first time landlord, and my first tenants just moved in. They had excellent references, rental history, credit scores and income. 

I drive past the property on my way to drop my son off at school in the morning, and it seems there’s 2 extra vehicles not disclosed on the application parked out front. It’s a four bedroom house, and the couple moved in about a week and a half ago.   

Should I be concerned that additional people are living there? Or as long as you keep receiving rents, don’t worry about it? A regular property manager wouldn’t be driving past at 7 AM and notice I’m sure… Thoughts?