They have to be reservists. In the reserves pt is more or less the responsibility of the soldier. Some courses in the reserves do have some time for pt but it is not a given. I did my BMQ on weekends and every Sat. and Sun. morning we had a short time allocated for pt due to the fact the all the candidates had to shower up and shave before the rest of the day began. On the longer courses they allot more time for pt then on the shorter courses such as weekend courses and co-op courses because class time is needed more on the short courses to get the material that needs to be covered rammed through the candidates heads.
It is in my opinion that if you are in the reserves you should go to the gym for pt at least 3 times a week to keep a suitable standard in pt. I hate the guys that show up to courses in the reserves and moan and cry about the pt being hard, dropping out of ruck marches, and runs then laying the blame on the instructors for not getting them ready.
Also, that if you are in the reserves and are not willing to keep yourself at a good level of fitness or do not have the discipline to do so one you have completed the BMQ and SQ courses the military is not for you, find somewhere else to go and complain because you are not willing to meet the requirements of your occupation.
You do not have to be a pt god or superman by any means just be aware that some of the work you will be doing is physically demanding, and that you should prepare yourself for said tasks.