DaMoshe,
“I think that a baal tefillah should choose tunes that are known by most people, so that this doesn’t happen. If there’s a tune that is familiar to you, then there’s not really a reason to not sing along, and the kehillah should join in.”
In some kehillos, lecha dodi is done responsively, with the tzibur repeating each stanza. Agreed that it’s a must for the shaliach tzibbur to be aware of what’s commonly done in the shul.