We had it raised to several thousand concurrent requests with no questions asked. YMMV based on age of account, amount of spend, etc.
It's not technological - it's about ensuring they have a reasonable handle on capacity and what they happen to have plenty of.
It's not a problem as long as you're not asking for astronomical limits, but people need to be aware of it and request increases in advance of starting to hit limits rather than assume it'll be near immediate to get them lifted.