Originally part of Dojo Rules published by the British Aikido Board now superceded copied below:
Practitioners should give account to the areas of formal conduct and respect for Aikido as suggested below, which also carry safety implications:-
1 The dojo is a formal space for the practice of Aikido and is dedicated to learning of budo, a martial 'way', in accordance with cultural and social traditions that have their origin in Japan. The maintenance of these traditions of behaviour give value and respect to the activity and its practitioners, and assist in developing personal ethical standards of behaviour and promote self-discipline. Practitioners are therefore required to observe the codes and forms of behaviour and their procedures as required by the dojo in which they practise.
2 When entering or leaving a dojo, practitioners must conduct themselves in a respectful manner, performing such rituals, salutations, or bows (rei) as required by that dojo.
3 Practitioners must treat the tatami, or mat area, on which they practise with respect in recognition of the safety it will afford them during the physical activity of Aikido. Therefore, salutations, as prescribed by the particular dojo must be observed before stepping onto the tatami and zori (footwear) left tidily at its edge.
4 Practitioners should continue to conduct themselves in a respectful manner, performing such initial salutations or bows (rei) as required by that dojo at the start and end of classes and during the practice.
5 When coming late to a class, practitioners should wait before entering the dojo until the instructor is not demonstrating so as not to distract their fellow practitioners; wait at the side of the tatami until they receive the acknowledgement of the instructor and permission to come onto the matted practice area; perform such salutations as required; when leaving early they must seek the permission of the instructor and again perform such salutations as required by that dojo.
6 Although Aikido is an activity within which each participant is accorded equal respect there will always be junior or senior (sempai/kohai) in the experience of Aikido to another and it is part of the formal tradition of Aikido that this superior experience is respected at all times.
7 During an Aikido class, formal salutations to a partner before and after practising with them is usual in all dojos and may be accompanied by a verbal acknowledgement in Japanese, such as “onegaishimasu”, or English - “Thank you”.