Theres
alot more to it than that

How Traditional is Your Aikido Dojo? Normally, the Floors/Mats (If Mats are used, Mats. If not, Floors) are Swept before and after each Class. As far as I can tell, its normally by Junior Students.
Its a Tradition, not a Labor. I can understand how it would come across as such at first.
The most Ive ever been asked to do is to push a box of Focus Mitts into a Cupboard; Which in a way, is Tidying up. I cant say I felt too exploited.
And since many Dojos are specifically Dojos, and not Rented Space that does other stuff as well, things like Painting the Walls not only benefit the Trainer, but also You, as a Student. And I doubt they had to Buy the Paint themselves anyway.
Granted, some places would exploit this, and thats a shame. But most of the time, its all in Good Faith.
And that is more descriptive of a McDojo.
Its ok for a Brown Belt to lead the Warmups or somesuch, but Teach the Class? No.
Theres a line between a Dojo being Commercial, and being a McDojo. The difference is, that one is there purely to make Money whilst keeping everyone happy (McDojo); The other Teaches a Martial Art, and operates to an extent for Profit. Among other things.
Also, apologies for the three Edits. Its tidier than Multiple Replies though.