Actually, Sunshine, it's not a bad system. It's just that most people have it ass-backwards.
The normal response is "they've gone under 5 games in a row...they HAVE to go over, right?..." Yeah, eventually. But you're better off going the other way.
Do some backtesting in O/U for NBA and MLB, as well as for W/L streaks in MLB. You'll see that it's far more profitable to follow a streak rather than chase the end of it. If a team is winning (in MLB - not as applicable vs the spread) it's because they're doing something RIGHT. Instead of betting on a team to finally lose after X wins in a row, it's better to bet on the win streak to continue after Y wins in a row. Then each night, keep it going. You can only lose once. It's more of a follow than a chase.
Same applies to O/U in MLB and NBA - although my stats for MLB are far more comprehensive than NBA. If I can find which old laptop my backtesting excel sheets are on I'll post them. Pretty damning stuff.
Good luck with your plays.