How to Undercut

[Seig345]

[...] once I mark your item back up. [...]

I find this back and forth banter of who’s getting one over on who very entertaining, but just wanted to point out that once you buy the item, it is now your item. Until SE adds a system that gives you play by play updates on each transaction of every item you ever sold after you sold it, no one is really incentivized to care beyond “hurray, the item I listed sold”.