The only place bets I make are on the 6 and 8(1.52%). That gives you 10 chances to win versus 6 ways of making a seven. I saw a kid roll the dice at the Casino Royale(Las Vegas) for 50 minutes and hit close to 30 six and eights before he sevened out. I would never pay the vig(4%) on the 5 and 9. The bottom line, correct or not, is everyone has the right to lose their "own" money anyway they want to playing a negative expectation game. Good Luck
By saying people have a right to lose their money makes you sound like a know it all. I'll tell you it is smarter to place the 5 and 9 as well and call your money off after two rolls than to just place the 6 and 8 and wait for your money to vanish after that 7 hits.