..rather should be on the ability of the site to onboard high influx of registration without shotting down , because I've come across some sites where everything looks good but was unable to withstand the influx of registrants.
When you said about high influx of registration, I was like how many people will visit the site in a minute. How you described the high influx is over exaggerated. Even the highly popular sites, do they actually have such high influx like a doing a registration update on her database which will end tomorrow.
Inline with what you are saying, the frustrating thing is when new sites makes deposit process smooth and easy, but withdrawal process difficult and frustrating.