The Google Calendar Location field accepts two placeholders. ADDRESS and CITY. I've integrated A+ with MarketPress. When adding a booking using MarketPress and submitting with "Access Google Calendar" ticked the location comes through with the address and city of the person making the booking. Shouldn't it use the location of the store?
Looking at the code, the call to function gcal( $service, $start, $end, $php=false, $address, $city ) seems to get address and city from post_confirmation which does indeed use the customer's address.