- drive to the government office (cost of transit)

- typically during business hours (non-free for hourly employees)

- provide some backing ID (otherwise, what's to stop somebody claiming to be me/you). That might not be free.

Basically, anything that might disenfranchise a protected class of citizen is going to have a tough time getting bipartisan support. Look no further than state-wide voter ID programs - almost all originate in conservative, GOP-led states - and almost all are thinly veiled attempts to prevent poor and minorities from voting (those two groups are more likely to support Democrats).