If this can save them money in the longterm and works then good on them. I like it when people think outside the box.
Cycling like mad for 5 hours produces 1 kilowatt of power. The cost of one kilowatt is about 12 cents, so in a week one bike would generate about $1 worth of electricity. If the equipment costs $100 it pays for itself in 2 years - might make sense, assuming it lasts longer than 2 years without breaking down and is really used 4-5 hours a day 365 days a year. In comparison riding a bike to work looks much better because you are transporting yourself not a 3,000 pound car.