@Neville Chaim Berlin – In communities where I have lived – both in town and out of town – I have seen, quite often, parents LEAVING their sons’ peyos after their upsherin (for example) and the son, then, leaving them “for life”. Sometimes the fathers eventually themselves add peyos, sometimes not. On rare occasions I have seen High School bochrim take them off (more out of peer pressure, I suspect). But usually they stay.
There is possibly a big difference between this scenario and one where the boy decides on his own to grow his peyos. Then, since it was not part of his chinuch (meaning his parents didn’t give them to him, or at least encourage it or praise the change), they are more likely to come off.