Its transparent to the users. In our enterprise a lot of users have Dell laptop with inbuilt wireless card and a PCMCI 100mb Ethernet card...and they work fine.
Even if the radio card it disabled the ethernet card starts functioning.
When both are connected, they both get Ip address, but I still have to check using a sniffer to see if both the cards rx/tx data.
So I am not sure if the throughput id incresased by using both connections.