I ACTIVELY make certain that I have spiders among the 'chids.
At this time of year, when it's move-everybody-inside time, I go looking for spiders that can "hang out" in the gh, and in the crowns of some of my humidity tray/light table specimens. I try to find varieties that tend to stay small and aren't very likely to travel, more likely to build a stable web and stay put. They have proved to be an absolute BOON in keeping down gnats in the sphagnum.
I also have a couple of the larger jumping spiders, who DO travel around...but they are pretty cool and rather beauty. One is a black one with a yellow spot on her back,(I think she is a Phippidus), the other is an Eris of some sort. Jumpers have incredible vision,(when most spiders have rather poor eyesight), and they seem to have personality that one doesn't see in "webbers".
These get around, but it's kinda cool to look over at the orchid table and see "Black Beauty" marching across the lanceanum in search of her brekkers....
I tend to keep whatever comes inside with the orchids.....prefer the spiders to the aphids and gnats and eater buggies any day.