You can't collect UI if you quit voluntarily.

i don't think it's hard to game the system. Recently, unemployment checks were sent out of country to foreign scammers, the identities of incarcerated felons were used to make fraudulent claims (successfully)... so i can't imagine it's much effort to fool the agencies involved

Based on anecdotal evidence it seems that you’re on the right track. California EDD was defrauded for millions and it was so embarrassingly bad that they shut down the system to many users. This forced them to live off of savings/family and live more frugally for months. Recently I’ve heard of many people being sent checks (back pay) for up to ~$10,000. It may not be that they’re still on UI but that they recently received lump sums that were designed to hold them over for months without working.