How to protect yourself and others when replying to business emails!

Tell people who you are CCing into an email: Make sure that when you send an email to multiple people you make it clear who has been copied in within the body of the email. This makes sure that everyone in the chain can easily spot any extra people who have made their way into the chain.
Check CC emails in a chain: If they don’t appear to be for people from the organisation you are talking to then remove the email and raise it with the person you are emailing, they may have been included by accident or they may have used technical skills to insert themselves in the conversation.
Let people know if you think you have been included in a chain by mistake: It is generally best to email the person who appears to have included you in the chain. If this happens then you should inform them immediately that you have been included by mistake and confirm that you will delete the emails. It is not only common courtesy to highlight this but is also part of good data practice.

Keep replying in email chains: It's good practice to delete all but the last email from a chain when replying. However helpful it may seem to be able to scroll back through the whole conversation, the increased risk with each email included means this just isn’t worth it! If you want to keep some context then keep the last email in the chain when you reply.
Forward other people’s email chains without thought: If you can’t be certain what is in your email chain, imagine what might be included in someone else’s! Just because they have bad data practices doesn’t mean you have to! Remove those additional emails and send on only the one that is needed!