I'd love to ssh to my server and use some modern MUA like Sup, but there are lot of places where you cannot ssh through local firewalls. When you work parttime

I'd love to ssh to my server and use some modern MUA like Sup, but there are lot of places where you cannot ssh through local firewalls. When you work parttime as a consultant or when you just meet with some potential customers/investors/cofounders/whomever you often need to use THEIR infrastructure. So what then? Do you imagine that you'd be unable to get an email from the people you're talking on the spot just because you need to tunnel somehow to your server? Bit weird.. One option is to always use own mobile connection, but still there are places where there's no carrier (like some server rooms), or you have to use customer's intranet at the same time you're relying on what's in your emails..