you know once your trainers get a hole in the sole and start letting water in?

surely it's time to bin the trainers and get a new pair you say. but these are thrifty times.

if one were to get some waterproof bathroom sealant, of the type that goes across the place where baths and sinks and things join to the wall, and inject a suitable amount of it into the hole, let it dry, would this fix the trainers and give them a few more months wear? or would it just fail miserably because of too much movement breaking the seal? has anyone ever tried this? i think i'm gonna try this.