It probably will be your neighbors that report the infraction to the HOA. It is these folks that, while coming and going, will see the work being done in a shared parking lot. Your neighbors likely know that the navy blue Accord belongs to Condo 2B even if they don't know you.
HOA have the ability to fine home owners here, and the fine doesn't have to be administered while the car is in service. A reporting neighbor only needs to take a photo or two for proof for including with the submission. HOA also have the ability to kick the owner out. Granted, this wouldn't be easy or cheap, legally, so it probably won't happen most places.
Rules don't only exist to annoy and inconvenience. A rule not followed is a step by the group toward chaos. People should either stick to the rules or work through the system to change the rules. This is a pretty basic tennant of community living.