Opening Lightning network channel: who is paying? When opening a lightning network channel between two parties, which of the following is true:

1) They must both pay a fee to open the channel

2) They might both pay a fee to open the channel

3) Just one party pays a fee.

The fee here refers to the bitcoin mining fee, not to the amount of BTC the two parties are putting in the channel.
Because a fee is part of a transaction, the fee must be paid by whichever party creates the funding transaction.

Don't think of it as paying a fee to open a channel, think of it as funding a channel with a transaction.  The fee just happens to be part of the transaction.  I believe the current spec has just a single party funding a transaction, but I see no reason why this could not be modified for parties to share the funding cost, in which case both would likely contribute to the fee.