A: You have a financial connection to the company that hired you and that relationship exists whether or not you are being paid for a particular tweet. If you are endorsing the conference in your tweets, your audience has a right to know about your relationship. That said, some of your tweets responding to questions about the event might not be endorsements, because they aren’t communicating your opinions about the conference (for example, if someone just asks you for a link to the conference agenda).
Also, if you respond to someone’s questions about the event via email or text, that person probably already knows your affiliation or they wouldn’t be asking you. You probably wouldn’t need a disclosure in that context. But when you respond via social media, all your followers see your posts and some of them might not have seen your earlier disclosures.
With respect to posting the conference’s badge on your Twitter profile page, a disclosure on a profile page isn’t sufficient because many people in your audience probably won’t see it. Also, depending upon what it says, the badge may not adequately inform consumers of your connection to the trade association. If it’s simply a logo or hashtag for the event, it won’t tell consumers of your relationship to the association.