It really depends on the variety as to the side shoot being removed and how they are being grown. If they are in a greenhouse or in neat rows with a variety like Alicante or Money Maker it's better to remove the shoots and keep them growing straight This stops the fruits touching the ground, it is good for air circulation which will prevent blight, easier to keep weeds down and easier to water. Lots of varieties are however bush type and are better left alone. The seed packet should say.