Not at all worried about anyone wanting to steal my 20 yo suitcase, or the clothes and toiletries in it. (On the return leg the clothes will need washing). The problem is more that if the bag check room is full, the employees discourage you from leaving your bag in it. Which is one of the best perks of the lounge. The agent will actually tell you there's no more room, and I've gone in there and rearranged a few items to make more room. In these instances, the agent simply cautioned me not to block the floor space, which I wouldn't do, in fact other people had left their bags on the floor and I ended up moving those too.
They really, really need a bigger storage room. Maybe not right now, but when traffic rebounds to pre-Covid levels, they do.