Streakiness
I have noticed perceived streakiness in many MG games. The problem is in proving that it is statistically significant as evidence of non-random game behaviour. While it is easy to show cases where such behaviour looks obvious, it is also possible to explain it away by using probability theory and showing that the event CAN happen, and that although rare, it has to happen sometime to someone.
The only way to mount an attack on such a proof is to design an experiment with enough of a sample size to show that the observed events have an extremely low probability of being pure chance. Secondly, the experiment has to be repeated and it be shown that this most unlikely event has happened yet again, and then again etc.
Designing experiments is not always easy. Looking at overall payout percentage, or even occurrences of individual numbers over a very large sample is not enough to disprove allegations of non-random behaviour. It is possible for roulette to be rigged to streak, but rigged in such a way that the long term outcome is that expected of a random game.
The idea would be to show that in the mid term, there are more biases than there should be if each result was completely independent.
Statistical correlation will be a good tool to look at (not easy, but can be done with software). This test looks for relationships between different variables. Choose two that should have no connection, and see if correlation between them exists.
For example, is a "2" more likely to be followed by a "13" than, say a "16" being followed by a "13". Using enough data, this should be a no. Such tests will show that the previous outcome has no bearing on the next (you might need to check many combinations).
I have run several experiments on various games looking for odd patterns. Sometimes, it looks like I have found something, but I find that on another attempt I cannot repeat the oddity. Some of the streaks have been truly remarkable in persistence. One in Vegas Strip level betting went on for 80,000 hands, and was very much in MY favour (for a change), to the tune of +800 betting units.