No lower limit! We don't have enough patch time (practice ice), to split it into high or low levels either. The after school and weekend morning sessions tend to have more lower level skaters though. I skate in the mornings, so most people are about my level or higher (MUCH higher in some cases!). Skating on the same sessions means I get to know who skates to what music, and even know the basic pattern of some of their programs so I know when to race for the boards and when it's ok to carry on what i'm doing.
Having said that, last week I was doing my program in my lesson, to music, and two of the coaches continually got in my way, and did nothing to move their skaters out of my way. Later on, doing landing positions in my field moves, I came within inches of kicking one of them, because she has ZERO awareness of anyone else, and after having to dodge her during my program, I wasn't gonna stop what I was doing for her.