Not exactly boned but it probably doesn't make practical difference to store "local time + tzinfo timezone" than just UTC time.
- You record an event occurring at local time
- You store it as UTC
- Local time zone definition changes
- Well whoop de loo, now you need to go through tzinfo to make sense of the past data anyway rather than relying on a known offset
Even if you store everything in UTC, you may be safe... but figuring out the local time is still convoluted and involves a trip through tzinfo.