i dont think GW will have any legal issues
The company is registered, no need for everyone else to register a business in USA.
Yes you do. It does not matter if they are registered. Every company needs to make sure that every business partner can be identified. To do that, they need to dox every customer. If said customers are i.e. using an offshore company, they can be sued by the IRS or every other national group for the support of money laundering, tax evasion or similar.
The fact that they are a registered business also means, that the IRS is regularly checking not only the book, but also contracts between customers and Giga. Mining in the USA is classified as a business as soon as you are doing it for profit and in a long term mater (the time frame does not really mater that much, but as long as you do it for profit you operate a business and you can't deny you do it for profit). Hence every customer needs to register their business activity with the authorities. You don't do it, Tax Fraud/Tax evasion. And therefore Giga is supporting it, resulting in possible law suits.
If they accept foreign nationals, its even more difficult and easy to fall into some tax problems....
Its one thing to have a miner in your garage, but a whole other thing if you run a business or in that case need a datacenter where your mining is on record for IRS. And it does not mater, where you live. EVERY COUNTRY got this rule of operating a business.
So the second you place your miner in another country you need to check if the placing of hardware alone is enough to classify as a permeant place of production....
And like it or not, they have no clue about any of these issues. Collecting money is one thing, making sure you are able to stay belly up another. This might have all been easy for them when they were operating only personal miners, now that they offer it to others, the legal base is a lot different....