Friend of mine used to be a casino worker. Roulette is not 'rigged' but the operator is trained to land the ball wherever he wants. Good operators will be able to land the ball with a 2-3 spot miss from their target spot. Based on that, it's pretty easy for specific number bets to be dodged. This is why you'd want to sit on a table that is populated.
Since there are devices which use a camera to visually estimate where a ball will land based on the speed and all, I think this would definitely be possible, but again extremely hard. However, it is hard for them to rig the odds/even bets. Only the number bets are what are unsafe to place as that can be manipulated to an extent.