"... friction for those few people who aren't always connected to their e-mail system." I'm not sure the size of this population is well understood to be able

"... friction for those few people who aren't always connected to their e-mail system." I'm not sure the size of this population is well understood to be able to label them as "few" - it may be few for a given set of services, but may be many for a different set of services.