Update for those using Kanchanaburi IO and TM30 requirements:
I returned from abroad on the 10th and on the 11th reported to the IO in Kanchanaburi. Luckily I had my landlord with me, as they asked for him, but just looked at him and his ID - I already had his signature on the form. Quickly got a new TM30 slip, which surprised me as I had heard from another poster that they were fining for in country stays outwith the province, not just when returning from overseas. Having been to Hu Hin in April for a week I suspected their system would throw that up and fine me, but nothing happened even though the IO accessed the computer before giving me the new slip.
All good, I didn't raise any issue so went to the second office for a new 90 day slip. On receipt I asked the IO if a TM30 was required for returning home from another province and she said yes, the hotel will log your stays so we need to know when you return. I asked her, given that I have a 320Km round trip home to office if I could go to Sangkhlaburi office which is only an hour away. The answer was no, but she suggested I sign up for the online TM30 system set up for hotels and landlords. Again this is contrary to another poster, who was told they couldn't use it. However I am planning to register and give it a go.
My plan is therefore to go in person if returning from abroad with anew TM6, and to use the online system if coming back from a different province after a holiday.
Confused? I am.
TLDR : Answer Summary
A user provided an update on the TM30 reporting process while returning to Kanchanaburi from abroad. They reported that they needed their landlord's presence to get a new TM30 slip, despite previous claims of stricter enforcement of fines for out-of-province stays. The immigration officer confirmed the necessity of TM30 for returning home from another province, but suggested using an online system for reporting, which contradicts other experiences shared in the community. The user plans to go in person when returning from abroad but will use the online system for inter-provincial returns.