But also each channel has to have the total amount being sent precommited in the initial channel opening so in your example if Alice want's to send Charlie 1 BT

But also each channel has to have the total amount being sent precommited in the initial channel opening so in your example if Alice want's to send Charlie 1 BTC the balance in both the A-B and B-C channels has to be at least 1 BTC. Which kind of demands some pretty central clearing hubs in the lightning network that will need a large amount of BTC locked into these channels.