CVent email fiasco - multiple offers confuse audiences

Brands often seem to get 'over-enthusiastic' about their email marketing.  As a consumer, I sign up to get messages from brands and I often get conflicting messages at the same time.

Take CVent - a brand promoting tools for events and conferences.  I got two different email messages from them yesterday.

One promoting a series of breakfast events and another offering me a voucher for attending a webinar.... Both to the same email address.  I'm not going to comment on the wrong-thinking or planning that could have avoided this scenario.... you can work it out.

What would you have done differently to prevent this?