Yes, for my case, I will wash it with detergent coz breast milk kinda oily if you never wash with detergent. After that, will sterilise it. No choice. Unless you dont't mind the breastshield oily..
I used to have a colleague who pumps at work, she also just wash it under tap water then put into a ziplock bag (specially for sterlising breastpumps) and heat up in microwave. Done within mins.