Obviously, it is not uncommon for "sharing" to occur between colleagues at the same company when it comes to fee based accounts or memberships. For example, a company may elect to purchase only one "seat" or account for a job board or other recruiting related resource, but then have multiple users access the tool. (I'm sure the vendors are fully aware of this situation even if their contracts and agreements prohibit this practice). 

I and others periodically receive LinkedIn InMail sent under one name (account holder) with an intro or explanation that the message is being sent on behalf of the account holder by a different person that identifies  him/herself accordingly.

It looks something like this:

Message appears to be from Mary Joe Cunningham's LInkedIn profile, but in the body of the message (her colleague) Jeremy O'Donald explains that he is the actual sender and he provides contact information and instructions to correspond back directly to him rather than Mary Joe. 

I've also received messages with the same scenario involving an account holder not being the actual sender, but the sender doesn't state that and it's not clear if the response should be addressed to Mary Joe (account holder) or Jeremy (shown in the signature line). 

I'm not even sure that it matters, as long as which ever person receives the reply back understands the context of who it belongs to. The main issue I see with the above communication is that it comes across a bit unprofessional and unnecessarily confusing when the sender doesn't clarify the situation for the person being InMailed. 

Thoughts?