One of the ways scammer alts are tracked down/trades with scammers are detected is through item history. As an example if 80% of someone's items are simply coming from and to a scammer, it's most likely an alternate accout of the scammer. If the person's inventory/profile is private, they have no way of doing this.
If you have nothing to hide, you shouldn't need a private inventory. If people are adding you to beg for your items, simply block them.

There actually is a way, letting users add a quantity subsitute to the items on the right would prevent this from happening.

Actually, they might get banned from outpost, but not marked on steamrep, because outpost considers you the alt of a marked user. You should appeal your ban since the account that they're considering an alt of yours is not marked anymore, but bear in mind that it doesn't mean that appeal will automatically get accepted.

Originally posted by Knurr:

What's so problematic about it?

I do not know for sure what Sneeza was reffering to.

Please, read this:
https://steamhost.cn/steamcommunity_com/groups/tf2outpost/discussions/0/558747922562007365/#c540742485382285410

The forums are not place to appeal site bans. This is also irrelevant to tf2outpost as you were banned because of your SteamRep report which resulted in a tag. You've already appealed your tag on the SteamRep forums, you will have to patiently wait for a response, then if your appeal gets accepted, appeal your ban on tf2outpost.com too.

https://steamhost.cn/steamcommunity_com/groups/tf2outpost/discussions/0/558747922562007365/#c540742485382216907

For example, people just put random cards from random games on the right or suggestive emoticons such as :tradingcard: and :tradingcardfoil: .

Well, it is not possible to have an icon on the right for every card that you are looking to buy, this is why people use placeholders.

Originally posted by LMAoK:

I would do that but it is alot less advertismen

It really doesn't work like that, people are not like : "let me go to tf2outpost.com and scroll down until I find what I am looking for" , there's a search function for filtering trades.

I guess that yes, but I cannot give a definite answer as I am not a staff member. My advise would be to create a bigger trade for all the cards that you are buying, so it will be a lot easier for people that are looking to generally trade cards for metal. There's only 8 slots, so you'd better use the items on the right as placeholders.