It really depends on whether the bubbles are all popping in the same place. A popped soap bubble does leave a tiny bit of residue and if they're all popping in close proximity it quickly adds up. Also in my (pretty extensive) experience smoke machines tend to leave quite a lot of their fluid on the ground near their output nozzle and bubble machines are very similar. You could put a tarp down to solve that problem easily enough but if the wind stays steady and all the bubbles waft to the same place to pop you're going to end up with a soapy wet spot. I've actually thought a fair bit about this exact issue in regards to a project of my own for the playa involving bubbles, smoke and UV light and the MOOPy residue was a big concern and part of why I haven't really pursued it.
And because this thread made me think of it here is a picture I took of a street artist in London last year, I watched him for a while and he really wasn't sloshing that much fluid around each time he loaded up but you can see it had added up over time around the bucket. That was what made me first start questioning the viability of my idea.
IMG_7821.JPG
I guess though really the question is, does it make a mess when you use it elsewhere? That's probably your answer. Also having re-read your original post I'm now wondering if maybe I've got the wrong end of the stick about your machine. I was thinking a high output professional unit like you'd see in a nightclub but if yours is portable maybe it's more like a kids toy..?
You do not have the required permissions to view the files attached to this post.