Well, steering wheel angle can easily contain some over-90Hz noise originating from the engine vibration coupling to the sensor or steering axis, and so on, and aliasing will transform that into low frequencies, making it appear someone is making slight steering actions while in reality is not.
But how much matters? Assuming this vibration has an amplitude of +/- 1 degrees, it won't also cause more than +/- 1 degrees aliased false signal with absolutely no filtration. Even very simple filtering is able to decrease that by 10x easily. This is why, often in practice, a combination of cheap analog RC filter and simple digital "blockwise" average suffices.
Also remember you need analog antialiasing before the ADC. The easiest today is to just use excessively high sample rate ADC, allowing you to use a crappy 1st order RC filter - for example, a 1MSPS ADC and 1st order RC with -3dB cutoff at 10kHz. Then filter and decimate digitally.
The idea is, whenever there is sampling, any frequency content over half the sampling frequency will alias. ADC does sampling, but decimation is also sampling, and the output rate of the decimator is what matters. And you need to filter before this sampling. Before ADC, it naturally can only be an analog filter, but before a decimator, it can be digital, with all the advantages of digital filters - especially steep transition and strong stopband attenuation, easily allowing you to use, say, 100Hz sampling rate which actually contains signals up to maybe 40-45Hz. But try to do that on analog and you are quickly in the rabbit hole of expensive components and hiring a seasoned analog designer.