They're not running thrusters continuously except during orbital transfer. Otherwise they'd run out of propellant pretty quickly even with a HET, and operating smallsats at 559km doesn't require that much orbital correction. They probably fire them far more often for conjunction avoidance than station keeping, but again that's a reported 300 total manoeuvres per day across 8k satellites, which gives them a bit of scope to time them for when they're unlikely to upset regulators

Interesting - yeah, that way they should have sufficient margin to plan the manuevers to avoid the radio telescopes. :)