I am the secretary of a strata committee where we have had the same problem – residents parking in visitor spots. This is a 35 unit complex with 8 visitor parking spaces. We have a by-law that regulate visitor parking to the effect that visitors may only park for 24 hours in a visitor parking spots in a seven day period. Then there is the general by-law which states that residents must not place their property on common property. In this case, parking their vehicles in visitor spots means that they are in breach of that by-law.
I monitor the visitor parking if someone lets me know that they have seen the same car in a visitor parking space for too long. I then check and if it continues, I issue a warning which I place on the windscreen, requiring that the car be moved. If there is no action, I issue a second notice in similar terms, but this time advising that I am moving the matter to our strata managing agent. If no response, that’s exactly what I do. The strata managing agent then issues a Notice to Comply and imposes a fee of $27.90 (or similar) for the issue of that Notice. The fee is charged to the owner’s levies. Owners can recoup this from tenants, I suppose, if it involves a tenant.
I have done this a few times with great results. No problems for the last six months (fingers crossed). By the way, the strata managing agent has drafted a by-law for the next AGM which specifically empowers him to charge fees for issuing Notices to Comply, although he already has an implied authority to do so.