Rakhdi / Rakhi is an implicit assurance exchanged between a brother and sister strengthening their devine relationship. Such Rituals, surely, eases out various communal and caste strains, stimulate compassion, unfasten outlets of expression, and present an occasion to revise our responsibility as individuals, most notably, bring happiness in our lives.
This protective bond symbolized by Rakhdi / Rakhi has resulted in infinite prejudiced ties among monarchies and states. The History of India gives evidences that the Marathas and the Rajputs queens had sent Rakhdis even to Mughal Sultans (Kings) who, despite their differences, had assuaged their Rakhdi-sisters by offering aid and fortification at vital instances and honoured the everlasting bond. Even nuptial alliances have been established between kingdoms through the exchange of Rakhdis.
For more information on Rakhi, Rakhi Origins, The History of Raksha bandhan, Raksha Bandhan celebrations in India Visit - http://en.wikipedia.org/wiki/Rakhi