Good question...

It appears that YiHi's approach at this point is replacement over repair. I had a cracked 510 seal (probably my fault) on my 1st SXmini. The vendor I purchased it from had no stock, so YiHi arranged an RMA though one of their USA distributors. The entire RMA process was only 7 days until I had a brand new SXmini in my hand. (including shipping it back)
I'll have to shoot an e-mail off to YiHi to ask how they plan on handling future RMA's on the S model...