On my recent trip round the US we'd have not flown at all on 7 out of the 10 days if we'd not flown when the freezing level was below MSA, because it was generally below zero at ground level. But then it was generally far below zero at cruising levels, which made ice less of a problem.
When encountering rime ice the general advice given was to ask for "4,000' higher" immediately. Around the south-east of the UK this too would be a problem, not experienced when flying IFR in the US.