The power of chilli and how tight is your band?

Just a couple of nights ago I watched the smoothest drummer swap I have ever seen.
Being involved in live sound production I get to see some interesting things.
Last weekend was a classic.
The band had eaten earlier and the drummer was doing fine - until the chilli kicked in and he had to leave for the bathroom - mid song.
A quick signal to one of the lead singers (who also played) and there was a smooth transition as drummers exchanged seats.
It was almost poetic to watch.
Not a beat was missed and the crowd kept grooving.

The lesson?
The band was tight and knew each other.
They had been playing together and professional enough to take any problem in their stride without being thrown.
This is why they get gigs every weekend and get invited back time and time again (and why I benefit with lots of stage work).

Keep it tight.
Practice together on a regular basis, know your material, know each other, get to know each other's style, communicate on and offstage and the groove will flow.