I just wanted to post this as it's a scam I see very commonly. Basically they say that they think you're a good player and send you a link to join the team. When you click the link and enter your information into the tournament website they have your steam information and then trade all of your items to multiple accounts. It happened to my partner and he was completely devastated as most of the items are unrecoverable and steam can't do anything to help. Stay clear of accounts like this
Source: https://www.reddit.com/r/DotA2/comments/17ws59g/heads_up_common_scam/