“按规定常到的人”可以翻译为 “people who regularly attend as required” 或者更简洁地表达为 “regular attendees as stipulated” 。
“people who regularly attend as required” 详细描述了这类人是按照规定经常到场的人。
“regular attendees as stipulated” 则更简洁，直接指出是按规定常到的参加者，其中 “stipulated” 意为“规定的”。
具体使用哪个表达可以根据语境和表达习惯来选择。