Re: 1xBit.com Coming back to Bitcointalk, Solving all the issues.
Placing a bet knowing that this bet is controversial to your previous bet, which will eventually help you to be in profit in any way - that's an example of unsportsmanlike bet.
I fail to see any problem with betting on different team after making a bet, it's possible user changed his mind or got additional information (such as news or other user analysis). Here's a meme.
Source: https://newfastuff.com/meme-generator/meme-generator-im-playing-both-sides-so-i-always-come-out-on-top/