I had the very same concerns a few months ago when I first installed Luma CFW on my 2DS.
The answer is a mixed bag.
First of all, when you decide to install CFW on any console, you must accept the risks of doing so in that you may potentially get banned from online services related to that console at any time, should you decide to connect to the internet with it afterwords.
With that, I suggest you take the proper precautions by using an online account that doesn't have any monetary value tied into it. Don't associate an account that you've used to pay for digital games, DLC, or any other purchases. Create a new account that won't be so devastating to you should you get banned in the future.
Console bans are also a possibility at some point. There's no 100% way to prevent a possible ban, so it's up to you to weigh the risks.
I would also like to suggest that should you decide to play online, don't use any cheats or game mods, as that would be the biggest red flag you could make. Don't be connected to the internet while using homebrew either.
If you follow these guidelines, you may reduce the potential of finding yourself banned at some point, but again it's never going to be a 100% thing. I've been playing online for months now following these rules and have been okay thus far.
Hopefully this will help you make a better informed decision on what you're willing to risk. I advise you to also do a little more research on your own, don't just take my word alone on this.
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That is cool... I have a switch and going online is a big no no. Why can you go online on the 2ds and not the switch
It may be that the 2DS's CFW entry points may be harder to detect in some way. I'm sure the Switch was designed better based on mistakes made with previous consoles, which is why it's harder to avoid a ban on newer consoles.
The risk is still there, however there may not be as many resources dedicated to the 3DS/2DS systems towards combating users installing CFW or engaging in piracy by the company, since the Switch is currently their main money maker.
One thing you can bet on is that console developers are increasingly working on bettering their detection methods and console security with each new generation.
I personally hate some of the decisions that console developers are making regarding new consoles just for the sake of preventing piracy. We're increasingly seeing newer consoles become more "locked down" with certain features and more of an emphasis on requiring internet access.
Looking at it from the company's point of view though, it's understandable that they'd want to protect their products value. Regardless what we, the consumers may want to see get kept in consoles, the developers also have bills to pay.
(I apologize for double-posting.
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