It's interesting - the violinst's right hand and arm are exactly how and where they would be if she were playing the instrument with a bow. However, the bow is missing from this image. The only way to play a violin without a bow is by plucking the strings (pizzicato). But then the right hand is in the wrong position for that.

Arguably, this could be grounds for the error tag.

Have you heard of air bowing?

z905844 said:

Have you heard of air bowing?

Only when it comes to air violins, but this is an actual violin.

Arima-san has his foot in position to use a footpump that appears to me to be absent from the image, too.