Possibly partially right for some situations! (that got enough get out clauses in it? ;-)
Pipework and TRVs are usually fine at pressure (just think about you mains water pipes etc).
Rads are also usually fine unless on the last legs - in which case the pressure change may push them over the edge and you will get pinhole leaks. However if this is the case they were due to do it anyway - you just accelerated the process by a few months. For a system treated with corrosian inhibitor on a regular basis this ought not happen anyway.
Old lockshield valves may weep when the pressure is increased. Having said that there is no guarentee they will (the ones on my system were fine when I converted it to sealed operation)