That metal pipe is most likely an "old school" fill line and they were probably just filling the pool while you were there. To test it out you could ask them to turn off the pool pump. If the water continues to flow it is not a "pool return" line but merely the fill line. It will only be on (manually) when the pool needs water and should not be a concern. If it turns off when the pump is off (which would be unusual) then it could be part of the pool return system, and so would be running whenever the pool is circulating, which is quite often. That would be a problem, but you rarely if ever see a pool return line routed over the coping, and if you do it is unconventional or a "hack" cure to some other underlying issue (like leaky underground plumbing) and should raise some red flags and warrant further investigation from a pool professional.
Chuck

If you buy that property, make sure you have that pool inspected buy a person who is certified, from top to bottom to prevent hidden costs later on. A couple of hundred dollars now could save you 20k down the road.

HI,

Thank you both for your replies. The pool was really full at the time so I dont why they would leave it running during a house showing. So it could be either, the house in general needed lots of work, and this was at 950,000!
So I will not be buying it. I hope whoever does, checks out the pool though.