Did this with a SEPA transfer on bitquick once. The guy sent me 180 euro. I saw the transfer go through to my account. I released the bitcoins.
2 days later my bank calls me and says the person's account that sent me the money was hacked and that they needed to refund the 180 euro. Nothing I could do at that point.
Yeah, this is why they introduced real name and ID verification at Localbitcoin. Bitsquare doesn't appear to have such protections, or indeed a rep system, but appears to rely on the assumption that hackers won't be bothered for sums of one Bitcoin or less...
That assumption is wrong. Scammers that sell fake anti-virus assistance usually charge their victims 200-300 euros. Note, IDs don't help in those cases, since the victims happily hand over their IDs to the scammers. You really have to look for the small details to discover that the sender of the money and the receiver of the BTC are not the same person. You can't do that on Bitsquare, as there's no direct communication between buyer and seller. I think that it's biggest weakness, as it may attract that type of scammers in droves.