If prostitution was legalised, raids on brothels such as these would be restricted in many ways. To uncover cases of trafficking or child prostitution they would need to get conclusive evidence (including affidavits from the victims themselves) that it was taking place. This rarely, if ever, is possible as the victims are unable or unwilling to give a statement. They may be unwilling because they have been blackmailed into submission or have been subjected to other forms of control. 

Property managers at high-end apartment buildings in Auckland, New Zealand (where prostitution is legal) said it took five months to remove a brothel from an expensive property in the Viaduct Harbour. One said prostitutes were openly soliciting other residents, but she couldn't evict them until they fell behind with their rent. The property managers complained to police and spoke three times to council officers. The council said two complaints were received and an investigation found no evidence of a brothel. 

If prostitution is legalised, ordinary, law-abiding citizens will always be on the back foot trying to protect their families and property.