Silly build idea:

Be on the forum for a while and you'll quickly discover some places self-built motorized bicycles aren't legal at all for use on the public roadways and it's strictly enforced. Other places they may not be legal but the police tend not to bother you as long as you obey the traffic laws.

Some places self-built motorized bicycles are legal but they also strictly enforce their guidelines. Other places where they are legal the guidelines may not be strictly enforced as long as you obey the traffic laws. It's primarily about where you live and secondarily about how you drive
Well said. Where you stand depends upon where you sit.