I frequently text an ETA to my hosts when flying on a longish trip.
Jamming masts? I don't really care if it does! I pay £40 PCM for my contract and if I can't use it during my day to day living that's their problem.
Is it safe?
Well, a 5 second text and then reverting to true VFR IMHO is much safer than having one's head glued downhill for hours on end to an iPad with SkyDemon installed, like some people seem to choose to.