Incy Wincy , Please Keep Out!

For nearly six months, Bob's Spider Rehoming System has been working very well. I am happy to use it to take offending arachnids to the end of the front path and release them onto the pavement. Except when it is dark, and I'm in my pjs and I spot a spider in the bath.
At such moments I drop the plastic pot over the creature, and it gets dealt with in the morning. This has happened a lot recently, as we approach September Spider Month.

Our bath has an overflow outlet the exact same size as the plughole. When we empty the bath [usually because the grandchildren have been in it] we 'park the plug'. But this means the spiders come up the regular plughole.
And if the plug goes back in the hole, then they squeeze their 8 legs through the overflow hole.
I was in the Futility Room when I had a brainwave! Back in Kirby in 1996, we had a kitchen sink with 2½ bowls, and only 1 plug. So I bought a red 'universal' silicon 'travel plug' to use when needed. And I have kept that in my 'laundry stuff' box for years.
Perfect solution.
There is no way Incy can climb up into the bath now. I still have the red bowls I bought for that kitchen. They are used every Friday for the orchid watering session. The flowers all gone now, the Sir David models are guarding the foliage.