One heavy downpour of rain and some tomato varieties will split quite easily. Even in the greenhouse irregular watering may cause toms to split, and the worse variety for splitting is Sungold.
However, Sungold is also the sweetest tom I've ever tasted, so it does have its good points!
Irregular watering is the main reason why tomatoes split so I water my toms even if they don't need it and when they do, I'll not give them too much.
If you see a plant wilting give it a spray mist of water but don't over-do the watering.
The good thing about cherry varieties like Sungold is that you won't get blossom end rot which affects mainly medium and large varieties. This means that the main consideration is to not over-water, rather than keep the entire soil area of the roots moist in order to avoid BER.