Recreational flying not a problem.

Flying for hire, eg. instructing, is a problem as any compensated flying counts towards your 30 in 7, 100/month and 1000/yr.

The first time you call your chief pilot to tell them you can't finish your 4 day trip due to a 30 in 7 problem because you instructed 7 hrs on your days off, well, you will be given a choice real quick. (And how are you going to fudge this in your logbook if you're doing it to "build time" as someone suggested?!)

Yes. Flight time/duty regs change in January. Will cause even more issues with required rest in 7 days.