A friend code needs an account: the code, and the list that survives a new phone, are what somebody would be adding you to. Starring people during a service works either way, and those are below.
Your people (0)
Star someone in a service, or swap codes above, and they'll show here. Your people are drawn larger with a ring, so they stand out without everyone else losing their colour.
Colours are yours alone — picking one for someone changes how they look on your map, not on theirs, and they never leave this phone. People you starred stay on this phone too; people you added by code follow your account.