Basicly me and my mate were riding about doing the midsumer quests in pirate mode due to Savory Deviate Delight. While riding the buff wore off but something else happened that made me lol, the side car had retracted with my mate still in it.
Not sure if this could be useful but thought id share with u guys too. Btw this isnt just client side as we both saw it. A theory which i couldnt test is that the side car may be able to be used by more than one person via this method but this is purely conjecture.
Edit: Feel free to try my theory and if proven wrong ill edit this post =P