What to take care of in Bali? - Don’t Touch People's Heads!
The soul is supposed to reside in one’s head, making it off limits for people to touch. Not even children (Balinese children, that is) should be touched on their heads, so no noogies.
The three causes referred to in the principle are
The human body is considered to have the head which is most pure because it is closest to the Gods. If you ruffle a Balinese child's hair it is considered a lack of respect.
The body self make good as mediator betwenn head and feet
The feet are considered most impure, being closest to the demons. That is why the Balinese kneel as you said and take their shoes off when entering their homes.
Everything is done to keep harmony between the Gods and Demons in the Hindu religion. Offerings are made to the Gods up off the ground on shrines and the Demons have their offerings put on the ground. Even the way their houses are orientated all have to do with Mt Agung which is considered the highest and most sacred being closest to the Gods.
We think as long as you respect their religion and culture, cover up to visit temples, be aware of offerings, speak politely and with respect it is all fine. The Balinese are used to us tourists coming to their beautiful island!
As “Western” and modern as much of Balipresents itself, the native culture of Bali provides a firm and tangible bedrock on which Balinese behavior and relationships are built. So if you’re going to visit Bali with a mind to visiting the island's temples and meeting the local people, you’ll need to mind your manners to stay on good terms with the locals.