FRRO / Registration when travelling (Pune)

Hi all,

I am doing an internship in Pune and I have registered at the FRRO. However, another intern who has gone back home now and who lives in Delhi asked if I would like to visit her. This would mean that I am going to Delhi by plane (this does not count as a visa entry since I am traveling within the country right?) and I will be staying at her place. Do I need to register again at the FRRO once I arrive in Delhi or should I fill in a Form C or anything because it isn't really clear to me what to do?

Further, my parents will be visiting in November and we will be going to Mumbai, Goa, Hampi and Kerala. During this trip we will stay in hotels and maybe an apartment from booking.com so I guess that they will fill in the Form C over there however, I am not entirely sure. Therefore my question: is there anything that I need to do when I am traveling through India, should I register again or something or is it okay now that I have registered once in Pune?

Thank you so much if you can help me with this because reading up on the FRROthing only scared me since I read that you can even go to prison if you didn't register properly(':