If you miss an entire day of work during a week, your employer may reduce your pay by a day for that week. Even if you worked extra another week (before or after), if you are a salaried employee, your employer may do this--that's because as a salaried employee, you receive no extra pay or comp time for working extra, so you cannot "bank" the extra time to make up for the day you missed. (Of course, an employer could let you make up missing time--but they are not required to.)If you drill on your own time (e.g. on a weekend, when that's not your regular work days) you cannot have your pay cut for it.