When you are tardy to school, and you are in my first block class, I will ask you to sign in at the front office to document that you were late. After that happens 4 times, there will be lunch detention. When you've reached 7 tardies, you will sit in ISS all day. After that, it's Out of School Suspension.
If you are going to make the effort to come to school--a laudable effort to make--take it just one step further and get to school with plenty of time to get into your first block class. It is inconvenient for all involved when you sit in ISS rather than being in class. Lateness negatively affects your grades, your mental health, and your school relationships.
For tardies to school AND for tardies in general to my class, THE BELL IS THE LINE. If you are walking in as the bell is ringing, I will cut you some slack. The determination of whether or not that happened is absolutely MY perogative. In other words, I decide if those things happened simultaneously. If you walk in even 1 second after the bell has rung, however, you are late. Multple tardies lead to consequences like lunch detention and ISS.
Arriving on time to class--and work--are life skills you can develop. Punctuality shows respect for those with whom you have engagements as well as showing respect for yourself.